AMD 8 Core vs Intel 8 Core

[arkie87]

So, i'm thinking about building a new gaming PC, and came across the fact that Intel 8 cores are $1000 while AMD's are <$200. Why is that? How much worse could an AMD 8 core be?

Also, would appreciate any references on building PC's, specifically, on liquid cooling.

Thanks!

[SAI Peregrinus]

Liquid cooling lets you use a bigger heatsink than you'd be able to use with air cooling. All the liquid really does is move the heat from the CPU to the (possibly external) heatsink/fan, it's still cooled to the outside air. It tends to be louder than air cooling due to pump noise, and won't cool things any better if the heatsink/fan are the same size as what you'd have with air. In general it's not worth the effort.

WRT AMD vs Intel, Intel has much better per-core performance, and KSP cares about single-threaded performance FAR more than multi-threading. So get the fastest single-thread CPU you can (hint: http://anandtech.com/bench/CPU/1028). Basically each Intel core is a lot better than each AMD core, but AMD can get you more cores for the same price, and most workloads for things most people do benefit from having extra cores so AMD is a good buy. But KSP is not most workloads, it's limited to a single core for the most demanding thread (the physics) and that's unlikely to change much soon. 1.1 might make it so different ships get different physics threads, but if you dock or build huge ships it will still need to be confined to one thread.

[Camacha]

Intel has a totally different architecture than AMD. The cores are not comparable at all. Intel cores are close to complete, discrete cores, each with their own hyper-threading too. AMD cores are somewhere between hyper-threading and full cores. Each set of 2 'cores' share a lot of architecture, much more than is the case with Intel. Calling them cores is a great marketing move and it is not really a lie, but it also suggests more than is true. Saying it is actually a quad core with fancy hyper-threading is equally valid.

Besides, comparing chips based on specifications is a fool's game anyway. The only proper way to gage performance is to look at benchmarks that were actually measured in real life scenarios. No artificial benchmarks and absolutely no comparing based on technical specifications. Find the chip you are looking at, preferably in a game you are looking at and see what it does.

Intel 8 cores are overkill for modern games and a waste of money, and hyper-treading generally is too. Something like a i5 6600K will give you amazing performance, without costing you an arm and a leg. If your budget is a little tighter, AMD might become interesting too, since they offer quite a lot of performance for a given amount of money, but it really depends on the game or specific application.

If would advise against water cooling, unless you really know what you are doing. If you want to do that right (so no ready made kits) it costs an obscene amount of money for rather small gains. Air cooling is highly effective nowadays, cheap, low maintenance, silent and easy to deal with. Unless you want to get into water cooling for the fun of it, there are more effective ways of getting better performance or more silent systems. Not to mention the hassle of emptying and filling your loop, the possibility of leaks (always fun near expensive electronics), the added weight, etcetera.

Edited August 30, 2015 by Camacha

[magnemoe]

Agree here, intel 8 cores are very fast but also expensive, they are also overkill for games.

Water cooling is just an issue if you overclock a lot or run stuff like the intel 8 core cpu.

I have an intel 6 core at 4 GHz and use water cooling to reduce noise as the cpu fan tended to run too fast, its an pre asembled set with an 12x24 cm radiator and two fans.

[PB666]

Intel has a totally different architecture than AMD. The cores are not comparable at all. Intel cores are close to complete, discrete cores, each with their own hyper-threading too. AMD cores are somewhere between hyper-threading and full cores. Each set of 2 'cores' share a lot of architecture, much more than is the case with Intel. Calling them cores is a great marketing move and it is not really a lie, but it also suggests more than is true. Saying it is actually a quad core with fancy hyper-threading is equally valid.

Hyperthreading on the intel is a technology that allows the logical splitting of cores. Its not neccesary for Intels function in most situation. On most computers you have alot of slow processes and a few fast processes. I upgraded a very old computer with a cheep early dual core and increased its windows speed many fold because it moved a RS232 process on a simulated dos emulator that needed to constantly check com1. This allowed the windows process to free itself. So if you are running something like creating 8 objects using new class instance, and each instance can run in the background, then the hyperthreading might be used. But most run when active and are silent in the background

I used to be a big fan of AMD, that waned because the lifespan of AMD processors was typically 6 years but Intel typically last more than 10. Most of the AMD processors I've thrown away were dead, most of the intel processors I've thrown away were obsolete. I have one computer that is a MMx 233 that I used as A server CPU overclocked to 250 because the Mb was designed for AMD that I used for 10 years and then it is are now on a machine that Runs an HPLC.

[cantab]

So, i'm thinking about building a new gaming PC, and came across the fact that Intel 8 cores are $1000 while AMD's are <$200. Why is that? How much worse could an AMD 8 core be?

Not five times worse, but certainly worse in a vast array of benchmarks.

I'd say that up to £150 or so - FX-8370, Core i5 4460 - the processor market is pretty competitive, with Intel and AMD offerings at any price point being pretty close overall, though KSP in particular will always do better on Intel. Above that price point though AMD just don't have anything that really matches fast Core i5's and i7's on performance, still less the "extreme" Intel processors. That allows Intel to charge what they think will get them the most profit.

A fun bit of history in the area. Back in mid 2013 AMD launched their FX-9590, "the world's first 5 GHz CPU", and asked around $800 for it putting it squarely against Intel's $1000 6-core i7 4960X. Within a few months the FX-9590's price was slashed to something like $250, while the Intel processor was still a grand. That says volumes about how AMD just couldn't, and still can't, compete at the high end.

[K^2]

Here is some insider perspective for you. Most modern PC games are optimized under assumption that you'll have four cores. Console games tend to be built around 6 cores, but CPUs on modern consoles are such fail, that if it's a straight up port, you won't be bottlenecking on CPU anyways.

Having more cores won't hurt, of course, so if you can afford an 8 core Intel, great! But if you have budgetting constraints, and are considering AMD CPUs, I wouldn't. Get yourself a quad-core Intel instead, and you'll still have better gaming performance.

[arkie87]

Thanks for all the replies.

I'm not really sure if i have an answer. Why is AMD 10x cheaper than Intel? Are AMD's also 10x worse?

Also, w.r.t. liquid cooling: does one buy separate kits for CPU and GPU or do GPU's not allow for liquid cooling? Also, does one need to buy a CPU meant for liquid cooling, or can any CPU be modified (by just removing the heat sink) for liquid cooling?

- - - Updated - - -

Liquid cooling lets you use a bigger heatsink than you'd be able to use with air cooling. All the liquid really does is move the heat from the CPU to the (possibly external) heatsink/fan, it's still cooled to the outside air. It tends to be louder than air cooling due to pump noise, and won't cool things any better if the heatsink/fan are the same size as what you'd have with air. In general it's not worth the effort.

Is this really true? While it is true that all heat is eventually rejected to air, liquid cooling is supposed to keep the processor a lot cooler, since the heat is removed more efficiently from the chip...

WRT AMD vs Intel, Intel has much better per-core performance, and KSP cares about single-threaded performance FAR more than multi-threading. So get the fastest single-thread CPU you can (hint: http://anandtech.com/bench/CPU/1028). Basically each Intel core is a lot better than each AMD core, but AMD can get you more cores for the same price, and most workloads for things most people do benefit from having extra cores so AMD is a good buy. But KSP is not most workloads, it's limited to a single core for the most demanding thread (the physics) and that's unlikely to change much soon. 1.1 might make it so different ships get different physics threads, but if you dock or build huge ships it will still need to be confined to one thread.

I thought 1.1 with unity 5 was supposed to change all that. Multithreaded physics... everything i've read so far has said that bigger ships will perform better. Do you have a reference to suggest it wont?

[K^2]

I'm not really sure if i have an answer. Why is AMD 10x cheaper than Intel? Are AMD's also 10x worse?

That's not how pricing works. At high end, demand for components becomes fairly inellastic. So very small changes in quality result in huge changes in equilibrium prices. This is particularly true because Intel has very little competition on the high end. Still, that $800 gap is there for a reason.

Also, w.r.t. liquid cooling: does one buy separate kits for CPU and GPU or do GPU's not allow for liquid cooling? Also, does one need to buy a CPU meant for liquid cooling, or can any CPU be modified (by just removing the heat sink) for liquid cooling?

Any CPU. You will need to install a special heatsink instead of the stock one. They do make water-cooling kits for GPUs. But it tends to be more work to install it. There are also water-cooling ready graphics cards out there. Just hook up the hoses and you're set.

Is this really true? While it is true that all heat is eventually rejected to air, liquid cooling is supposed to keep the processor a lot cooler, since the heat is removed more efficiently from the chip...

Water cooling only transfers heat. It doesn't remove it. In fact, it's impossible to just get rid of the heat. It has to go somewhere. In air-cooled system, heat goes directly from CPU heatsink to air. Which limits cooling rate by surface area of the CPU heatsink and air flow.

With water-cooling, water transfers heat from CPU heat sink to a larger external heatsink, which usually can be significantly larger and allows for better airflow. But yes, eventually, all that heat still has to go into air.

[Hagen von Tronje]

Intel's octocore is a state of the art CPU intended for high end applications. It's certainly much more than up to the task of gaming but it's really meant for workstations.

AMD octocores are frankly mid tier CPUs.

The key thing to keep in mind is that most (not all) games are more dependent on one or two strong cores than having a lot of cores. A quadcore i5 with great single core performance will do much better for you than an octocore with weak single core performance. Very few games can do anything useful with all eight cores from either manufacturer.

CLC units don't impart miraculous cooling. Their main attraction (to me, anyway) is stabilization, they produce far fewer heat spikes than a fan. They're also good for displacing heat, as the heat will be moved to the radiator which may (or may not) be more convenient for your design than blowing it out the back of the case, and they can raise the ceiling on overclocks if you want to do that. However, I've never once heard the pump on one without trying to stick my head inside the case to do it, tiny high-speed GPU fans are many orders of magnitude noisier than either the pump or the radiator fans on mine.

But are you talking about CLC or custom/full immersion? There's quite a difference both in what you can expect out of it and expense/difficulty and risks. What are you trying to get out of it? Just great gaming performance, or do you want a computer to tinker on, or a competitive overclocker, or what? Full immersion on an X series Intel is maybe a little ambitious if you just want to game.

[Ten Key]

High end Intel CPUs also serve the scientific computing market-- they're pretty good for building "cluster" computers. AMD CPUs are not really designed for that kind of number crunching. The extra demand there probably helps keep the prices up.

[Camacha]

Hyperthreading on the intel is a technology that allows the logical splitting of cores. Its not neccesary for Intels function in most situation. On most computers you have alot of slow processes and a few fast processes. I upgraded a very old computer with a cheep early dual core and increased its windows speed many fold because it moved a RS232 process on a simulated dos emulator that needed to constantly check com1. This allowed the windows process to free itself. So if you are running something like creating 8 objects using new class instance, and each instance can run in the background, then the hyperthreading might be used. But most run when active and are silent in the background

I used to be a big fan of AMD, that waned because the lifespan of AMD processors was typically 6 years but Intel typically last more than 10. Most of the AMD processors I've thrown away were dead, most of the intel processors I've thrown away were obsolete. I have one computer that is a MMx 233 that I used as A server CPU overclocked to 250 because the Mb was designed for AMD that I used for 10 years and then it is are now on a machine that Runs an HPLC.

Hyper-threading is a small bit of extra hardware architecture. This tiny bit of extra hardware allows is faster switching of (CPU) tasks. This ensures the chip is idling less while switching tasks, making more efficient use of the portion doing the actual calculations. So while the OS sees double the cores, only a small bit of extra chip is active. Most of the chip is (almost) exactly the same as a non hyper-treading chip.

Programs that benefit the most from this are programs that switch a lot between tasks. A famous example is a video task, which consists of relatively simple calculations that need to be done many, many times over.

liquid cooling is supposed to keep the processor a lot cooler, since the heat is removed more efficiently from the chip...

Yes, the heat will be removed more efficiently, but no, it will not be a lot. You might be able to overclock a chip a little bit further when cooled with water, but much more than a couple of hundred MHz it will not be. Those gains are great for benchmarks, but yield little to no actual real life performance that you will notice. It is an awful lot of trouble for something you will not really notice.

Intel's octocore is a state of the art CPU intended for high end applications. It's certainly much more than up to the task of gaming but it's really meant for workstations.

At stock speeds, the newest Skylake quadcores will outperform the Intel octocore in most applications, unless it is a properly threaded app. Even when it comes to workstation-ish tasks, like CAD design, a quadcore often is the better choice. When you start looking at overclocking both to the maximum and doing almost perfectly multi-threaded tasks like rendering, the hexacores and octocores start gaining ground.

If you just want to game, be smart and buy an i5. It will be as fast as an i7 in almost every game, overclock well and be relatively cheap to boot. It is just the perfect choice for gaming. If you want to do other things too, it really depends on those other things, but generally an i5 is plenty good.

I always say that if you do not know why you would need an i7, you do not need an i7. There are a couple of specific scenarios those make sense and those scenarios do not apply to most people.

High end Intel CPUs also serve the scientific computing market-- they're pretty good for building "cluster" computers. AMD CPUs are not really designed for that kind of number crunching. The extra demand there probably helps keep the prices up.

When it comes to pure number crunching, AMDs actually do quite well. Those kinds of tasks often scale very well over multiple cores. The problem is the power consumption: if you light those cores up 24/7, a cheaper chip that consumes more power will quickly vaporize your initial gains. When it comes to servers and super computing, saving even a little power can make an upgrade worth it. And I hate to say it, but that is where AMD currently loses out.

Edited August 31, 2015 by Camacha

[arkie87]

That's not how pricing works. At high end, demand for components becomes fairly inellastic. So very small changes in quality result in huge changes in equilibrium prices. This is particularly true because Intel has very little competition on the high end. Still, that $800 gap is there for a reason.

Makes sense. Comparable Intel and AMD cpus might be priced (linearly) proportional to their performance, but higher end, it becomes non-linear.

Any CPU. You will need to install a special heatsink instead of the stock one. They do make water-cooling kits for GPUs. But it tends to be more work to install it. There are also water-cooling ready graphics cards out there. Just hook up the hoses and you're set.

Thanks for the info.

Water cooling only transfers heat. It doesn't remove it. In fact, it's impossible to just get rid of the heat. It has to go somewhere. In air-cooled system, heat goes directly from CPU heatsink to air. Which limits cooling rate by surface area of the CPU heatsink and air flow.

With water-cooling, water transfers heat from CPU heat sink to a larger external heatsink, which usually can be significantly larger and allows for better airflow. But yes, eventually, all that heat still has to go into air.

[Camacha]

Makes sense. Comparable Intel and AMD cpus might be priced (linearly) proportional to their performance, but higher end, it becomes non-linear.

There is no linear proportionality when it comes to computer chips. Cheap chips are often relatively expensive (since shipping, packaging, personnel and store costs remain the same) and the top tier is relatively really expensive too. It is a bit of a wonky curve, I guess

Yes, technicalities aside, what is the advantage?

Did you read my post? The gains generally are slim. Something like 200-400 MHz, though it can be more or less, depending on the chip and cooling. It is generally not enough to be noticed by the user without benchmarking.

If the performance gain is so minimal, why do people do it? If the performance gain is just shrinking the heat sink size on the CPU, who cares?

Because some people want the best result possible for 24/7 computing (since more exotic forms or cooling are generally not feasible for every day use), other people like to fiddle with complex things for the fun of it and yet more people like to show off with their contrived contraption.

In short, water cooling is a hobby for most, not a necessity.

[arkie87]

Did you read my post? The gains generally are slim. Something like 200-400 MHz, though it can be more or less, depending on the chip and cooling. It is generally not enough to be noticed by the user without benchmarking.

Sorry, may not have read in full. Got a lot of responses...

What limits the gains to 400 MHz? Chip voltages and/or computer crashes? Or chip temperature i.e. liquid cooling isnt much better than a well-designed air heat sink...

[Camacha]

What limits the gains to 400 MHz?

Let me be clear, 400 MHz is just an estimate. There is nothing that limits chips under water to that specific gain, since there many factors that play a role. I just meant to indicate that the gains are fairly minor. Maybe I should not have given a specific example - let us just say it is a handful of percent instead.

Chip voltages and/or computer crashes? Or chip temperature i.e. liquid cooling isnt much better than a well-designed air heat sink...

It is mostly temperature. Water is still a room temperature liquid, so while it is somewhat more effective at removing heat, the difference is small. A lot smaller than it would be with liquid nitrogen or even helium. As a result, the overclock gains are relatively small too. They are there, but when you look at all the money and time invested, it hardly seems worth it unless you just want to fiddle with water cooling for the fun of it or do exceptional computational things.

The second part of the deal is the fact that air cooling has matured in the past few years. When the step was made from pure heat sinks (block 'o metal) to heat pipe type coolers, huge steps could be made. By now, heat pipe coolers are very well developed and amazingly good at what they do as a result. Water cooling used to provide much more of a gain, because air coolers used to be much less advanced.

Edited August 31, 2015 by Camacha

[arkie87]

Let me be clear, 400 MHz is just an estimate. There is nothing that limits chips under water to that specific gain, since there many factors that play a role. I just meant to indicate that the gains are fairly minor. Maybe I should not have given a specific example - let us just say it is a handful of percent instead.

I am mostly concerned with the cause of the limit, rather than the specific value of the limit.

It is mostly temperature. Water is still a room temperature liquid, so while it is somewhat more effective at removing heat, the difference is small.

I dont understand the logic here. Water is 20x better than air at transferring heat (0.5 W/mK vs 0.025 W/mK thermal conductivity). A well designed water cooler should be able to keep the temperature much lower than an air cooled one. The only reason this wouldnt be the case is because of the thermal interface materials (TIMs) which might account for the bulk of the thermal resistance; in this case, you either have to bypass the TIM or use cryogenic fluids.

[Camacha]

I dont understand the logic here. Water is 20x better than air at transferring heat (0.5 W/mK vs 0.025 W/mK thermal conductivity). A well designed water cooler should be able to keep the temperature much lower than an air cooled one. The only reason this wouldnt be the case is because of the thermal interface materials (TIMs) which might account for the bulk of the thermal resistance; in this case, you either have to bypass the TIM or use cryogenic fluids.

You are pretty much right there. Delidding is a popular pastime among overclockers, and absolutely necessary if you want to play with the big boys. A packaged chip can only expel heat so fast.

Please note that plainly looking at air versus water conductivity does you little good. Heat pipes are nifty devices that use the vaporizing of a liquid in a vacuum to transfer heat. Air is only used in the final stage, but the same can be said about water cooling. Calling air cooling does current coolers little justice, calling them vapour phase cooling systems would be more accurate. Like I said: this type of coolers is really quite good compared to heat sink air type coolers. It is effective and compared to water robust, cheap and almost fool proof. They spread heat over a large area to help poor air conductivity along, just like water cooling does.

Edited August 31, 2015 by Camacha

[arkie87]

You are pretty much right there. Delidding is a popular pastime among overclockers, and absolutely necessary if you want to play with the big boys. A packaged chip can only expel heat so fast.

Please note that plainly looking at air versus water conductivity does you little good. Heat pipes are nifty devices that use the vaporizing of a liquid in a vacuum to transfer heat. Air is only used in the final stage, but the same can be said about water cooling. Calling air cooling does current coolers little justice, calling them vapour phase cooling systems would be more accurate. Like I said: this type of coolers is really quite good compared to heat sink air type coolers. It is effective and compared to water robust, cheap and almost fool proof. They spread heat over a large area to help poor air conductivity along, just like water cooling does.

Even heat pipes wont help if a TIM is thermal bottleneck.

Microchannel water coolers can be just as good if not better than heat pipes, though heat pipes are passive (which is both an advantage and a disadvantage).

[K^2]

Precisely. And the most common reason to use water cooling is because heat-sink-to-air is the bottleneck. In which case you have to either use a much larger external heat sink and water cooling, or you can go with active cooling and force heat into heat sink.

[arkie87]

Precisely. And the most common reason to use water cooling is because heat-sink-to-air is the bottleneck. In which case you have to either use a much larger external heat sink and water cooling, or you can go with active cooling and force heat into heat sink.

Are you saying heat sink to air is the bottleneck OR that when it is, switching to liquid cooling helps?

Pumped liquid cooling and heat pipes can easily achieve thermal conductances greater than the TIM, making the TIM the bottleneck. If the TIM is not the bottleneck, then switching to liquid cooling should give significant improvement, no?

[K^2]

Are you saying heat sink to air is the bottleneck OR that when it is, switching to liquid cooling helps?

The later.

Pumped liquid cooling and heat pipes can easily achieve thermal conductances greater than the TIM, making the TIM the bottleneck. If the TIM is not the bottleneck, then switching to liquid cooling should give significant improvement, no?

If your external heat sink has the same parameters as your CPU sink, then liquid cooling will make things worse, since you now effectively have two TIM layers. The whole point is that you still have an external heat sink with much greater area and better ventilation than the heat sink you could possibly place inside. This is why we started talking about water cooling still being air cooling in the end. It just lets you be much more efficient about it.

As for TIM being a bottleneck, if that's the case, the only way to combat it is active cooling. You can increase the heat flow through TIM by increasing temperature gradient. Since you want CPU to stay cool, you need to make external temperature positively frigid. You can either use thermoelectric cooler between CPU and liquid cooler, or you can put your liquid through a refrigerator. Both are done occasionally for extreme overclocking.

[PB666]

Hyper-threading is a small bit of extra hardware architecture. This tiny bit of extra hardware allows is faster switching of (CPU) tasks.

http://www.intel.com/content/www/us/en/architecture-and-technology/hyper-threading/hyper-threading-technology.html

Allows the running of two threads on a single core for applications designed to take advantage of it.

[magnemoe]

If your external heat sink has the same parameters as your CPU sink, then liquid cooling will make things worse, since you now effectively have two TIM layers. The whole point is that you still have an external heat sink with much greater area and better ventilation than the heat sink you could possibly place inside. This is why we started talking about water cooling still being air cooling in the end. It just lets you be much more efficient about it.

As for TIM being a bottleneck, if that's the case, the only way to combat it is active cooling. You can increase the heat flow through TIM by increasing temperature gradient. Since you want CPU to stay cool, you need to make external temperature positively frigid. You can either use thermoelectric cooler between CPU and liquid cooler, or you can put your liquid through a refrigerator. Both are done occasionally for extreme overclocking.

Today with heat pipes this is true, heat pipes works almost as well as water cooling downside is that they are solid so you are limited to 12 cm heat sinks and fans internally. water cooling lets you get past this up larger sizes.

10 years ago before heat pipes water cooling was more relevant as the traditional coolers don't work as well

[K^2]

Today with heat pipes this is true, heat pipes works almost as well as water cooling downside is that they are solid so you are limited to 12 cm heat sinks and fans internally. water cooling lets you get past this up larger sizes.

10 years ago before heat pipes water cooling was more relevant as the traditional coolers don't work as well

Sure, but external heat sinks on yeolde water-cooled systems had the same limitation. They were pretty crap, so you had to have a significant sized heat sink, usually sitting on the side of your expansion tank.