A question about building my own PC

[gutza1]

I am planning to build my own PC to replace the laptop that I was using. I want it to be good at performing many tasks, and I require it to be capable of running KSP with tons of mods installed and a heavily modded Minecraft server. I also may be recording video and audio for a let's play. What components should I get to achieve my goals without going overboard (I want either a high-medium end or low-high end build)?

[K^2]

Depends on your budget. But I would strongly recommend going with at least four physical cores, and at least 600 series GeForce GPU.

Modern games are getting better and better at utilizing multiple cores, and 4 cores is the typical target. (In part, because XBox One runs 4 cores.) Having multiple cores also improves your multi-tasking performance, so if you are recording or streaming, a CPU with 4+ cores will keep things running smoothly.

nVidia introduced ShadowPlay with their 600 GeForce series. It was developed primarily for their Shield tech, but one of the advantages is that it lets you stream or record gameplay without tying up your CPU for encoding. In other words, you can be recording your gameplay without any performance degradation.

For a solid mid-range PC, I'd build it around an Intel Core i5-3750K Ivy Bridge CPU and probably GeForce GTX 760 graphics card.

The rest of the components don't make a huge difference. You just want everything to be compatible, and you want it to be reliable. For the later, check reviews. Personally, I try to stick with ASUS motherboards, but that might be personal bias. Basically, if you go with 3750K CPU above, just start looking for an LGA 1155 board that has all the features you want and has the size that matches your tower. It also needs to have a slot for your graphics card (PCI Express 3.0 for basically anything modern), but hardly any motherboard these days doesn't come with at least one. (And you only need multiple if you plan to SLI, which is not really a mid-range sort of thing to do.)

An LGA 1155 board will also almost certainly come with DDR3 RAM slots, so you'll need to pick DDR3 memory. At least 8GB for a mid-range. I like Corsair, but again, read reviews. And the board will also come with some number of SATA ports for HDDs. You probably don't need RAID, so essentially anything will do. With HDDs, just read reviews, and look for capacity that works for you. Western Digital and Seagate tend to be pretty reliable, but absolutely all brands of HDDs vary from model to model. Seriously, read reviews.

That basically leaves optical drives (hardly even matters what you chose at this point) and PSU. PSU is important. Don't go cheap. Last time I was replacing PSU, I've found one that looked like a bargain, only to discover that while it doesn't fail often, its principal mode of failure was catching on fire. You want your PC flaming hot, but not literally. It might feel like you are wasting money, paying twice as much for a PSU with good reviews, but you just don't want to be part of statistic on this one. Best case scenario, it burns out and you have to buy a new one. Worst cases are just, ugh. Common PSU-related problems cause anything from frying your other components to a literal fire.

All that's left is finding a case to stick all of that into. Basically just get anything you like. The case usually supports certain sizes of motherboards which are called form factors. Make sure these match. And if you are putting a lot of crap into it, make sure it's a big enough box. But that's about it.

There are a whole lot more considerations, from specialized cooling systems, to solid state and hybrid memory. But these don't really fall into mid-range sort of pricing. So the only real choices you are going to get is which CPU and which GPU to build your PC around. Everything else will fall into places once you decide.

P.S. There are several pieces of hardware typically integrated into modern motherboard. Ethernet, USB ports, and audio. For most people, all three are quite sufficient. But if you happen to be an audiophile, you will definitely enjoy benefits of a specialized board. For all of such things, however, the question is basically how much money you are willing to part with.

Edited November 16, 2014 by K^2

[sgt_flyer]

lets start from KSP point of view :

for mods, one of the key components is memory usage. (there's some mods which allows to limit memory usage by using compressed textures though, or even loading textures only as you need them.)

however, the 'stable' version of KSP is currently 32 bits - so it won't be able to handle more than 4 gigabytes of memory. (however, the OS itself also use some memory, so you can have more than 4Gigabytes of memory.)

CPU wise, KSP use a single thread for physics calculations, which is the true bottleneck on KSP performance. the more parts you have for it, the more CPU power will be used for physics. - so you'll need a CPU capable of high performance on a single thread (high Ghz CPU).

the graphic card is not the most required element (unless you play with high res texture mods). also, Nvidia or AMD doesn't really matter - (KSP don't use Graphic card based PhysX calculations)

now, on top of that, you want to do streaming and running a dedicated server.

you'll need a CPU capable of having a good number of threads (physical cores would be even better), to spread the load correctly among the CPU cores. (video processing/compression can use a lot of CPU power and some memory - not accounting for high hard drive space requirements if you record it in raw to compress it afterwards - if you do streaming, your processor wi'll have to run compression on the fly - quite hard )

a dedicated server will also use one or more threads for it's calculations on top of that, along with quite some memory.

i'd guess you'll want at least a 4 core processor, or even a 6 core one with high Ghz speeds. (Hyperthreading would eat a bit of each core max performance to add 'virtual' cores. which could be useful for video processing, but less for running KSP physics - could be useful, but not mandatory.

regarding memory, having the OS,modded KSP, a dedicated server, and video recording/editing will all use quite some memory - 16 or even 32 gigas of memory could be useful there.

the graphic card would be the least concern, a medium - high end card in the 200 - 250$ range would be enough to cover most of your needs (unless you plan to play to more recent games - in this case, having a more recent graphic card can be enough to last for a few years).

you'll of course need a dedicated big hard-drive for when you'll be recording your play sessions (especially if you do the video compression/editing afterwards) - so this hard drive won't impact much performance on the others.

a SSD can be of some use concerning loading times and such, and is comfortable to use as an OS disk.

so we would look at 1 SSD (no need for a high capacity one, and their prices have dropped quite a bit) + two hard drives at least. (and maybe some external storage for storing all videos)

so you'll still need a configuration quite beefy in the CPU and memory department for running all those things in parallel

Edited November 16, 2014 by sgt_flyer

[K^2]

sgt_flyer brings up a good point on HDDs. If you plan to record, at a minimum, you want a HDD from which you run the game, and a HDD to which you are going to record the video. The bottleneck here is seek time, so by having reads and writes go to different drives, you make sure that recording the video doesn't degrade performance of the game.

SSD is totally optional, though. It's only really useful for the OS. Hybrid drive is probably a better choice for the game drive, but we are starting to get into not-so-mid-range sort of prices.

If you are worried about HDD performance/reliability, Western Digital's VelociRaptor series is a pretty good compromise for reasonable price.

[Jouni]

Gaming PCs seem to be really strange beasts. If I were to build a low-end non-gaming PC, I would start with 16 GB of memory, a 256 GB SSD, and a decent 24" display. With those, you could probably use the system two years from now without suffering too much.

Of course, it might just be that our definitions of "low-end", "mid-range", and "high-end" don't match.

[gutza1]

lets start from KSP point of view :

for mods, one of the key components is memory usage. (there's some mods which allows to limit memory usage by using compressed textures though, or even loading textures only as you need them.)

however, the 'stable' version of KSP is currently 32 bits - so it won't be able to handle more than 4 gigabytes of memory. (however, the OS itself also use some memory, so you can have more than 4Gigabytes of memory.)

CPU wise, KSP use a single thread for physics calculations, which is the true bottleneck on KSP performance. the more parts you have for it, the more CPU power will be used for physics. - so you'll need a CPU capable of high performance on a single thread (high Ghz CPU).

the graphic card is not the most required element (unless you play with high res texture mods). also, Nvidia or AMD doesn't really matter - (KSP don't use Graphic card based PhysX calculations)

now, on top of that, you want to do streaming and running a dedicated server.

you'll need a CPU capable of having a good number of threads (physical cores would be even better), to spread the load correctly among the CPU cores. (video processing/compression can use a lot of CPU power and some memory - not accounting for high hard drive space requirements if you record it in raw to compress it afterwards - if you do streaming, your processor wi'll have to run compression on the fly - quite hard )

a dedicated server will also use one or more threads for it's calculations on top of that, along with quite some memory.

i'd guess you'll want at least a 4 core processor, or even a 6 core one with high Ghz speeds. (Hyperthreading would eat a bit of each core max performance to add 'virtual' cores. which could be useful for video processing, but less for running KSP physics - could be useful, but not mandatory.

regarding memory, having the OS,modded KSP, a dedicated server, and video recording/editing will all use quite some memory - 16 or even 32 gigas of memory could be useful there.

the graphic card would be the least concern, a medium - high end card in the 200 - 250$ range would be enough to cover most of your needs (unless you plan to play to more recent games - in this case, having a more recent graphic card can be enough to last for a few years).

you'll of course need a dedicated big hard-drive for when you'll be recording your play sessions (especially if you do the video compression/editing afterwards) - so this hard drive won't impact much performance on the others.

a SSD can be of some use concerning loading times and such, and is comfortable to use as an OS disk.

so we would look at 1 SSD (no need for a high capacity one, and their prices have dropped quite a bit) + two hard drives at least. (and maybe some external storage for storing all videos)

so you'll still need a configuration quite beefy in the CPU and memory department for running all those things in parallel

The most I'll be doing is both recording and playing video games. I just want enough computer power to be able to build my warp-drive equipped KSP Interstellar mothership or build the modded minecraft factory of my dreams without the ridiculous amounts of lag that I get when I try to do those tasks on my current computer.

Edited November 16, 2014 by gutza1

[cantab]

For a solid mid-range PC, I'd build it around an Intel Core i5-3750K Ivy Bridge CPU and probably GeForce GTX 760 graphics card.

Why would you not get a Haswell-based system, especially since Haswell Refresh improved overclockability, and I'd expect the latest features would be on LGA1150 motherboards more than the older ones.

however, the 'stable' version of KSP is currently 32 bits - so it won't be able to handle more than 4 gigabytes of memory.

...

the graphic card is not the most required element (unless you play with high res texture mods). also, Nvidia or AMD doesn't really matter - (KSP don't use Graphic card based PhysX calculations)

Only on Windows is 64-bit KSP unstable. On Linux it's perfectly solid, allowing you to use multiple memory-heavy mods (typically those with a lot of parts) without having to do memory-reducing workarounds. And if you do plan on playing KSP or any other game on Linux then the graphics card consideration changes: nVidia's drivers are significantly better, which really tips the balance in their favour.

Anyway, there's a big thread for PC building. I won't be surprised if a mod merges this one in.

[K^2]

Why would you not get a Haswell-based system, especially since Haswell Refresh improved overclockability, and I'd expect the latest features would be on LGA1150 motherboards more than the older ones.

It'd be a touch more expensive. But you'd also get a more future-proof motherboard with 1150, sure. So there isn't anyr eason not to go with Haswell. It's just that there is a lot of ambiguity in mid-range on where you should and shouldn't cut costs.

[Camacha]

sgt_flyer brings up a good point on HDDs. If you plan to record, at a minimum, you want a HDD from which you run the game, and a HDD to which you are going to record the video. The bottleneck here is seek time, so by having reads and writes go to different drives, you make sure that recording the video doesn't degrade performance of the game.

SSD is totally optional, though. It's only really useful for the OS. Hybrid drive is probably a better choice for the game drive, but we are starting to get into not-so-mid-range sort of prices.

If you are worried about HDD performance/reliability, Western Digital's VelociRaptor series is a pretty good compromise for reasonable price.

And please, don't forget to make backups. Any data you don't have on two separate disks is data you don't care about.

Backups are love. Backups are life.

It'd be a touch more expensive. But you'd also get a more future-proof motherboard with 1150, sure. So there isn't anyr eason not to go with Haswell. It's just that there is a lot of ambiguity in mid-range on where you should and shouldn't cut costs.

Intel chips typically barely drop in price when replaced by newer generations. If you can get a good deal, sure, the past 3 generations are all pretty close from a performance point of view. When there is little difference price wise, going for the most recent technology might be the smart thing to do. Especially if you can get some new standards like M.2 slots on there.

Gaming PCs seem to be really strange beasts. If I were to build a low-end non-gaming PC, I would start with 16 GB of memory, a 256 GB SSD, and a decent 24" display. With those, you could probably use the system two years from now without suffering too much.

Very specific user cases aside, 16 GB is quite a lot. Most games are not even going to use 8 GB properly.

Edited November 17, 2014 by Camacha

[K^2]

We are getting better at using memory past 4GB. So this is going to change very soon.

Because modern consoles are so PC-like, a lot of optimizations we do target XBox One or PS4, and are directly carried over to PC. Then, we add compatibility hacks for any system that doesn't measure up to these standards. That means that you need to have at least as much RAM as a console does, so that the game doesn't get thrown into some sort of internal compatibility mode.

With modern consoles, that means 4 cores, SSE4 support, 8GB of RAM, and DirectX 11. Of course, you need to go out of your way to build a modern mid-ranger and not hit all of these.

[Jouni]

Very specific user cases aside, 16 GB is quite a lot. Most games are not even going to use 8 GB properly.

There's an old rule of thumb for buying memory. First you determine how much you need, and then you buy double that amount, unless it's too expensive. If you only buy the amount of memory you usually need, using the computer is going to be painful, if you want to do something unusual, there's a memory leak somewhere, or something goes wrong.

[sgt_flyer]

yup - 16GB would be a lot for most games - however, gutza1 also plan to run a minecraft server and / or do recordings at the same time on the same computer each of those can end up using memory too (not accounting for the OS memory requirements )

now, without knowing what kind of budget / which OS gutza1 would want to use, it's a bit difficult to calculate which components would suit his needs, we can only offer explanations on how he can determine what he would need

[trekkie_]

I can tell you what you need.

8GB of DDR3 1333Mhz (or any higher frequencies if they're the same price).

i5 4690 (k or non k version depending on if you want to overclock)

Cheapest socket 1150 motherboard (again, depending on if you want to overclock, but cheapest will do just fine, or cheapest of a trusted brand)

Almost any videocard in the $200-$250 range, probably AMD is a best bet for cheap and performance. nvidia can be a little greedy....and AMD's mantle works on intel, not that you'll need it.

Transfer what you can from old PC, like hard drive and power supply if possible. If not, a 120GB Samsung SSD hard drive minimal will be a good investment. Samsung makes great SSD's.....fast and reliable. I got one for $80 years ago and its been amazing. Has handled terabytes worth of data written.....and at 500MB/s....everything loads FAST.

Also best to use a regular hard drive for storage and downloads, stuff like movies, music, pictures, etc. If you have to buy a new power supply, then just make sure it's enough wattage (6oow would be enough for virtually any single card system) and has the right type of power hookups for your videocard.

that's a system that should last any modest person at least 3-5 years.

Edited November 17, 2014 by trekkie_

[sgt_flyer]

@Kerbtrek - be sure to read what the OP asks before posting a configuration - it's not just for playing

at first, the OP is currently on a laptop, so he won't be able to reuse a lot of is old components

then, as he want to use the system for recording it's play sessions, he'll need at least 2 hard drives (in addition to an optionnal SSD (though he could go with using 1 hybrid drive for it's system + games, and a second drive for recording it's play sessions) - especially if he want to create let's play videos, he'll need a system able to make video edition (having two hard drives can really help for that )

(of course, not counting for the use as a server the OP wants to do in addition to the rest )

[K^2]

That's also the reason to go with nVidia over AMD for graphics. While there is software out there that will use GPU compression on AMD cards (e.g. Raptr), nVidia's ShadowPlay does it with zero hit to performance and works out of the box for absolutely any game. So if you are interested in recording and/or streaming, I'd definitely go with nVidia, even if it is going to be slightly more expensive. Better support on Linux is another reason. Windows support tends to vary from generation to generation, but currently both nVidia and AMD are doing pretty well, so there isn't a major difference there.

[Javster]

Please, don't make the mistake I made and go for a cheapish PSU without enough cables to power your GPU.

[Camacha]

There's an old rule of thumb for buying memory. First you determine how much you need, and then you buy double that amount, unless it's too expensive. If you only buy the amount of memory you usually need, using the computer is going to be painful, if you want to do something unusual, there's a memory leak somewhere, or something goes wrong.

There is currently one good reason to load up on DDR3 memory - it is only going to get more expensive. DDR4 is on the horizon and prices for DDR3 have almost doubled in the past two years. This happened before with pretty much every ageing type of memory. Once it gets more expensive because it is slowly being replaced, it is only going to get worse. I doubt you are really going to need more than 8 GB in the next 3 years, but with price developments in mind you might want to buy some extra to be sure.

In general I would advice against your rule of thumb though, as memory that is sitting idle is money ill spent. Buy what you need and maybe a little extra, but don't go overboard. You keep seeing systems with ridiculous amounts of memory that will never get used.

Please, don't make the mistake I made and go for a cheapish PSU without enough cables to power your GPU.

I have said it before and I will say it again: a good PSU is the basis of a stable and pleasant system (along with a reliable hard drive and proper backups). Forget mega turbo 10.000 watt PSU's, get an appropiate A-brand power supply and you will not regret it - it is an absolute necessity. Cheap PSU's are a source of problems and pain.

Edited November 17, 2014 by Camacha

[LaytheAerospace]

Straightforward build.

1. Load up on CPU power, it's going to serve you best in all your activities. Ignore core count, and forget that AMD exists as a CPU company. You want the best Intel chip you can afford, preferably a K series if you're willing to get your hands dirty overclocking. Skip the hyperthreading enabled chips, it won't buy you any performance in your use cases, and adds another $100 in cost. This means the 4570k or the 3570k. Save the $20 and drop the k edition if you don't want to overclock.

2. 8GB of memory is plenty, but don't let anyone tell you to settle for DDR3-1333. Sure, memory speed is a tiny part of your computer's performance, but it's also a tiny part of the cost. Return on investment for getting faster memory is actually higher than most other components that people routinely drop much more money into. This makes sense when you think about it. If you spend 3% of your computer's cost to gain another 5% performance, that's a really good deal. And that's what faster memory does. Resist the urge to buy more than 8GB, though. Free memory provides no performance benefit, you only need enough to let every application allocate as much as it needs. For almost everyone, that's 8GB. And if you need more than 8GB, it's trivial to add more later. No reason to go straight to 16GB before you know your usage.

3. For a video card, I'm a lifelong user of AMD cards, but have been recommending Nvidia for some time now. AMD's drivers are just awful, they always have been and they're not getting any better. Nvidia, on the other hand, keeps doing really awesome stuff with their software. Aim for the $200-$250 price point, which is the best bang for your buck. That's probably the GTX 760 or something like that. Tom's hardware does a monthly "best video card for your money" article that's been very good when I looked in the past.

4. Storage! Given that you're going to be recording footage, you really need at least two drives to avoid thrashing the disk and making the computer slow to a crawl. So get an SSD, at least 120GB (for OS and other stuff you want to load quickly), and pair it with a large HDD. Keep in mind that a 120GB SSD is going to need you to manage the disk space pretty regularly to keep it from filling up.

5. Get a decent PSU. If it costs less than $40, it's probably garbage (though I have seen cheap units that didn't suck). Corsair's builder series are good mid range units that should last, and cost around $50-$70. I'd consider this a minimum bar for any gaming computer.

6. Last but not least, the motherboard. With the exception of the high end, there's really not much to differentiate motherboards. The biggest differences between a cheap uATX board and a mid range ATX board will be connectivity. You'll get more PCI-e slots, more USB 3.0 ports, more SATA 3.0 ports on the more expensive boards. USB can be expanded easily and cheaply later, but SATA and PCI-e cannot. If you think you might want multiple video cards one day, make sure your motherboard has multiple PCI-e slots. If you want to connect a ton of high speed drives, make sure it's got enough SATA 3.0 ports. Most of the rest is fluff (though often very nice fluff, it doesn't make the computer any faster).

CPU wise, KSP use a single thread for physics calculations, which is the true bottleneck on KSP performance. the more parts you have for it, the more CPU power will be used for physics. - so you'll need a CPU capable of high performance on a single thread (high Ghz CPU).

Clock speed is only one aspect of a computer's single threaded performance. Intel chips, while having much lower clock speeds than AMD chips, are much, much faster clock for clock. As a result, single threaded performance on Intel's 3.5 GHz chips is actually better than competing AMD chips running at 4 GHz+.

i'd guess you'll want at least a 4 core processor, or even a 6 core one with high Ghz speeds. (Hyperthreading would eat a bit of each core max performance to add 'virtual' cores. which could be useful for video processing, but less for running KSP physics - could be useful, but not mandatory.

Six core processor means AMD (or overpriced Intel, also not recommended). AMD processors are strictly inferior to Intel's. Their instructions per cycle is much lower, and the bulldozer architecture shares the floating point scheduler between modules, effectively cutting your usable cores in half when it sees floating points. Given that KSP is the rare CPU limited game, I'd strongly recommend staying away from AMD CPUs at all costs. They're cheaper for a reason, folks.

regarding memory, having the OS,modded KSP, a dedicated server, and video recording/editing will all use quite some memory - 16 or even 32 gigas of memory could be useful there.

16GB is wasteful unless you know your memory footprint is going to be higher than 8GB. 32GB is ludicrous unless you're using applications which can scale performance to available memory, which are primarily related to editing high resolution video and photos. I don't think editing the relatively low resolution video for a Let's Play is likely to require an especially large amount of memory.

so we would look at 1 SSD (no need for a high capacity one, and their prices have dropped quite a bit) + two hard drives at least. (and maybe some external storage for storing all videos)

Why external? It's not like he's going to be swapping drives out like video professionals do. Save the cost of the enclosure and put the drive in the case with the rest. Also, a single SSD + HDD is fine. More HDDs isn't going to give more performance, and he can always add another drive later if he runs out of space.

Gaming PCs seem to be really strange beasts. If I were to build a low-end non-gaming PC, I would start with 16 GB of memory, a 256 GB SSD, and a decent 24" display. With those, you could probably use the system two years from now without suffering too much.

What's with everyone recommending 16GB of memory? The other 8GB is just going to sit there and do nothing. We're well past the days of getting more performance out of more memory for 99.9% of people, including power users.

We are getting better at using memory past 4GB. So this is going to change very soon.

It will change, but not soon. It's not a question of whether or not we know how to use memory. You just use it. The problem is the large installed base of computers without much of it. Software developers target their efforts at the hardware their customers are likely to use. Depressingly, that's a laptop with a dual core processor, 1280x768 display and 3GB of memory. Really, though, this isn't much of a problem. Most software can't make use of large amounts of memory, because it simply doesn't need it. In fact, most software already can't make use of the memory commonly available to crap laptops.

Edited November 17, 2014 by LaytheAerospace

[Camacha]

2. 8GB of memory is plenty, but don't let anyone tell you to settle for DDR3-1333. Sure, memory speed is a tiny part of your computer's performance, but it's also a tiny part of the cost. Return on investment for getting faster memory is actually higher than most other components that people routinely drop much more money into. This makes sense when you think about it. If you spend 3% of your computer's cost to gain another 5% performance, that's a really good deal. And that's what faster memory does. Resist the urge to buy more than 8GB, though. Free memory provides no performance benefit, you only need enough to let every application allocate as much as it needs. For almost everyone, that's 8GB. And if you need more than 8GB, it's trivial to add more later. No reason to go straight to 16GB before you know your usage.

Performance gains are really minimal, somewhere in the 1 to 3% range. If the costs are about the same, go for it, but otherwise it seems to be money wasted. I agree with the rest of your memory related comments though.

4. Storage! Given that you're going to be recording footage, you really need at least two drives to avoid thrashing the disk and making the computer slow to a crawl. So get an SSD, at least 120GB (for OS and other stuff you want to load quickly), and pair it with a large HDD. Keep in mind that a 120GB SSD is going to need you to manage the disk space pretty regularly to keep it from filling up.

Don't forget proper backups. Those are hardly ever taken into account when building a new computer, while they are oh so important.

I am going to repeat myself until everyone is sick of it and then repeat it some more

[LaytheAerospace]

Performance gains are really minimal, somewhere in the 1 to 3% range. If the costs are about the same, go for it, but otherwise it seems to be money wasted. I agree with the rest of your memory related comments though.

It really depends on the overall cost of your computer. Say you're comparing a $50 kit vs a $80 kit, on a $1k computer. Let's say that the $80 kit is 3% faster, then for another $30, you've increased the performance of the computer by 3% for 3% cost ($1030/$1000 == 1.03) and broken even. Not a compelling upgrade. Now let's try it again on a $1500 computer. That $30 is only 2% of the cost, but still about the same 3% performance. At $2000, it's only 1.5% of the cost, returning double its cost in performance.

For such a modest cost, I'm generally of the opinion that you might as well unless you're dealing with strict budget limitations. Most people can find another $30 for the budget, or at the very least the $10 it takes to go from DDR3-1333 to 1600.

[Jouni]

I doubt you are really going to need more than 8 GB in the next 3 years, but with price developments in mind you might want to buy some extra to be sure.

16 GB was a lot of memory four years ago. It felt like that for a year or two, but everything kept using more and more memory, and now it's just the average. If you're sure you're only going to use software with low memory requirements, such as office suites, browsers, and most games, 8 GB should still be enough. For other applications, 16 GB is the minimum for comfortable use.

Right now, I have KSP running with a rocket on the launchpad, with Firefox, LibreOffice, and a few other applications in the background. OS X reports that I'm using around 13.5 gigabytes of memory, out of which around 4.5 GB serves as disk cache. With more aggressive memory management, all of this would fit in 8 GB, but there would be noticeable delays when switching applications.

In general I would advice against your rule of thumb though, as memory that is sitting idle is money ill spent. Buy what you need and maybe a little extra, but don't go overboard. You keep seeing systems with ridiculous amounts of memory that will never get used.

Computer specs should be based on peak loads, not typical loads.

What's with everyone recommending 16GB of memory? The other 8GB is just going to sit there and do nothing. We're well past the days of getting more performance out of more memory for 99.9% of people, including power users.

Memory is about convenience, not performance. It allows you to keep software running in the background when you're not using it, making the computer more enjoyable to use and speeding up workflows.

I'm about to replace this old Mac with a separate gaming PC and a new work Mac as soon as I've finished moving to a new country. The gaming PC will probably have just 16 gigabytes of memory, as games don't need much. The work Mac is going to be either an iMac with 32 GB of memory or a 64 GB Mac Pro. With 32 GB, I could keep the Linux virtual machine running in the background, which is easily worth the price of the extra memory. 64 GB would make it possible to run some experiments locally, speeding up development cycles. I'm still not sure whether it would be worth the cost, however.

[Camacha]

16 GB was a lot of memory four years ago. It felt like that for a year or two, but everything kept using more and more memory, and now it's just the average. If you're sure you're only going to use software with low memory requirements, such as office suites, browsers, and most games, 8 GB should still be enough. For other applications, 16 GB is the minimum for comfortable use.

Don't be ridiculous Without wanting to make myself the definitive benchmark, I tend to have fairly heavy workloads, with complex CAD software including simulations, a RAMDisk that eats up some RAM, high-end rendering software, browsers with a large amount of tabs, several Adobe programs open and sometimes popping in and out of games for the occasional relaxation. Even then 8 GB is pretty hard to fill. Your computer must have terrible memory management if what you are saying it true, but it sure is not typical. Only very specific user cases tend to make good use of 16 GB memory, specifically running multiple VMs or using specific editing software like After Effects.

Just look at computers being sold. The cheaper half of the market comes with 4 GB and the upper half with 8 GB. 16 GB is pretty rare, for good reason. And though I am the first to admit that ready made systems often are unbalanced, techwebsites that do know their stuff also advice 4 to 8 GB for new builds.

Computer specs should be based on peak loads, not typical loads.

That rather depends on how often you encounter those peak loads. If you are going to hit 8 GB+ only a couple of times a year, you are going to do just fine with swapping that little bit of data to the hard drive (especially if that is a modern SSD). If you encounter it on a weekly or even day to day basis more memory is advised. If you buy all your hardware based on peak load you are spending a lot of money for something that will sit idle almost its whole life.

I'm about to replace this old Mac with a separate gaming PC and a new work Mac as soon as I've finished moving to a new country. The gaming PC will probably have just 16 gigabytes of memory, as games don't need much. The work Mac is going to be either an iMac with 32 GB of memory or a 64 GB Mac Pro. With 32 GB, I could keep the Linux virtual machine running in the background, which is easily worth the price of the extra memory. 64 GB would make it possible to run some experiments locally, speeding up development cycles. I'm still not sure whether it would be worth the cost, however.

Just remember that it is a lot cheaper to install memory in a Mac yourself, rather than buying it with the computer. Be sure to check out the details before doing any purchase though, there is lots to be found on the internet about this.

Edited November 18, 2014 by Camacha

[LaytheAerospace]

16 GB was a lot of memory four years ago. It felt like that for a year or two, but everything kept using more and more memory, and now it's just the average. If you're sure you're only going to use software with low memory requirements, such as office suites, browsers, and most games, 8 GB should still be enough. For other applications, 16 GB is the minimum for comfortable use.

This just isn't true. I can run two web browsers with 100+ tabs, IntelliJ IDEA, Altium, LTSpice, Plex Media Server, Apache and Kerbal Space Program and not come close to my 8GB of memory. I don't even have the swap file on. If 8GB weren't enough memory, then my computer would be crashing all the time from memory allocation errors. I assure you, it does not.

Right now, I have KSP running with a rocket on the launchpad, with Firefox, LibreOffice, and a few other applications in the background. OS X reports that I'm using around 13.5 gigabytes of memory, out of which around 4.5 GB serves as disk cache. With more aggressive memory management, all of this would fit in 8 GB, but there would be noticeable delays when switching applications.

That's your problem, right there, OS X. It inflates your memory usage to try to get any use out of it, often with poor results. Things got a lot worse with Mavericks, too. You don't need more memory, you need an OS that does less silly things with the memory you already have. FYI, I'm typing this on a MacBook Pro. It's my primary work machine (I'm a software engineer), and I'm constantly frustrated with its memory management. Like when my applications are using less than half my available memory, but OS X decides to start paging anyway so it can use the rest of my memory as a file cache.

Basically, OS X's memory management is designed to utilize every byte of memory that it can, to the point that it will stuff useless things into memory, and hang onto dead pages long past when it needs to. This supposedly works very well for some common use cases, but it does a terrible job in my experience. I've heard getting an SSD helps a lot with the paging (work won't pay for the SSD, I'm not going to either), but I'd rather just have an OS that didn't page unnecessarily in the first place.

Memory is about convenience, not performance. It allows you to keep software running in the background when you're not using it, making the computer more enjoyable to use and speeding up workflows.

And my Windows computer with 8GB of memory and the page file disabled does just that.

I'm about to replace this old Mac with a separate gaming PC and a new work Mac as soon as I've finished moving to a new country. The gaming PC will probably have just 16 gigabytes of memory, as games don't need much. The work Mac is going to be either an iMac with 32 GB of memory or a 64 GB Mac Pro. With 32 GB, I could keep the Linux virtual machine running in the background, which is easily worth the price of the extra memory. 64 GB would make it possible to run some experiments locally, speeding up development cycles. I'm still not sure whether it would be worth the cost, however.

What are you doing development on? The only thing I can think of that would actually use that much memory is rendering or compositing. As a software developer, I can run literally all my tools simultaneously without coming close to a total footprint of 8GB.

[Jouni]

Don't be ridiculous Without wanting to make myself the definitive benchmark, I tend to have fairly heavy workloads, with complex CAD software including simulations, a RAMDisk that eats up some RAM, high-end rendering software, browsers with a large amount of tabs, several Adobe programs open and sometimes popping in and out of games for the occasional relaxation. Even then 8 GB is pretty hard to fill. Your computer must have terrible memory management if what you are saying it true, but it sure is not typical. Only very specific user cases tend to make good use of 16 GB memory, specifically running multiple VMs or using specific editing software like After Effects.

I think you misunderstand the purpose of a memory manager. It's not supposed to minimize the memory usage, but maximize the performance and minimize the delays. If there is enough memory available, a good memory manager often uses much more of it than the minimal amount required to run the same workload with a decent performance.

There are basically three resources a memory manager handles. One is the memory used by applications. If memory is scarce, the memory manager can move inactive pages to disk, freeing physical memory for other purposes. Moderate swapping causes potential delays, while excessive swapping degrades performance.

Another resource is disk cache. Because random reads are ridiculously slow even with the fastest SSDs, having a lot of cache is still as useful as ever. If more memory is needed, disk cache can usually be freed quickly, unless there are a lot of queued writes. The optimal cache size depends on the workload, but it's often a significant fraction of physical memory. Having too little cache can cause unnecessary delays, increase loading times, and reduce the overall performance.

The third main resource is free memory. Usually it's a good idea to have enough completely unused memory that you could start a fairly memory-hungry process without the memory manager interfering. If there is too little free memory, large memory allocations can cause delays, as the memory manager has to free some used memory.

My example workload was quite typical for me playing KSP. On this 16 GB desktop, OS X uses 9 gigabytes of application (and system) memory and 4.5 gigabytes of disk cache, leaving 2.5 GB free. When I quit KSP, the memory manager keeps the amount of disk cache the same, while increasing the amount of free memory to 4.5 GB. I also have similar workloads on my 8 GB laptop. While the performance is generally good, switching between applications is noticeably slower, even though the laptop has a faster SSD.

Just look at computers being sold. The cheaper half of the market comes with 4 GB and the upper half with 8 GB. 16 GB is pretty rare, for good reason. And though I am the first to admit that ready made systems often are unbalanced, techwebsites that do know their stuff also advice 4 to 8 GB for new builds.

That's actually another rule of thumb I've been using. If PC manufacturers have X amount of memory in their cheapest models and 2X in their typical models, 4X is the amount I should be aiming for in a basic desktop. So far it's been quite accurate, as I've always considered the memory and the display the most important components of a desktop system. (For the last 5 years or so, I've also included a large enough SSD among the key components. Hard disks have been obsolete for a couple of years, except for storing large amounts of bulk data.)

What are you doing development on? The only thing I can think of that would actually use that much memory is rendering or compositing. As a software developer, I can run literally all my tools simultaneously without coming close to a total footprint of 8GB.

I develop algorithms for bioinformatics and information retrieval. Prototypes often use tens of gigabytes of memory, while only the sky is the limit for production systems. And even if we ignore the prototypes, Linux virtual machines typically require 4-8 GB. Like most computer scientists, I prefer OS X over a Linux desktop, but sometimes the OS X just isn't compatible enough with the standard tools.

[GregA]

Someone has to take one for the team.

http://store.apple.com/us/buy-mac/imac

Get the 21.5" with the 750m graphics card.

My only issue with that would be I like my 42" monitor, it would be hard for me to go back to something as small as 27"