Trying to choose a new CPU

[Barefoot Friar]

I'm about to upgrade my computer. I can't decide on a chip, and I'd like to ask for some help. Here's the info I have:

• I use it mainly for KSP and general web browsing, word processing, etc. KSP is by far the most demanding piece of software I run.
  
• I run Linux -- Ubuntu, to be exact.
  
• I am going to invest in 8GB of RAM, and the board I get will be expandable to at least 16GB.
  
• I have narrowed down my choices to either the AMD FX-8350 8-core at 4.2Ghz OR the Intel i5 4670K at 3.8Ghz. I want to spend about $250 on the chip and motherboard at the moment, and both of those are in the neighborhood. Actually, the AMD is $50 cheaper and looks to be slightly faster in most multi-core processes, assuming I'm reading the benchmark numbers right.
  
• The i7s look nice, but I can't afford them.
  
• I am not opposed to finding an older 32-bit or 64-bit chip that will run KSP especially well; I have enough boxes and hard drives that I could actually put together a system dedicated to KSP. However, I would prefer to build for the future and be able to use the new chip for my usual stuff and my gaming.
  
• I am not currently planning to buy a dedicated video card, but I can be pursuaded. Ubuntu really only plays well with nVidia, and even that is a bit of a hassle sometimes.
  

I understand KSP for Linux has a 64-bit version, but I don't know anything about it. Does it utilize more than a single core? I thought the problem with 64-bit KSP was the fact that Unity is 32-bit at the moment, so I don't quite know what to think. Can someone shed some light on this for me?

I'm not necessarily all AMD or all Intel. Most of my chips have been AMD, but that's more a function of familiarity and price than anything.

Oh, I've seen the CPU Performance Database thread, and am working my way through it at the moment. From the looks of that thread, the i5 is the favorite.

[Xaiier]

Since you've narrowed the choices down so much already, this is easy. The Intel chip is going to be substantially better. More cores means nothing to KSP so the 8 core is not going to be better in any way, in fact it would probably be worse as Intel chips tend to be better per-core, which is why Intel chips cost much more than AMD ones that seem to be much superior. Also, the 4670K can be overclocked to well over 4.2 GHZ so if you are willing to overclock you are going to get substantially better performance.

I actually just bought one for my new machine so yeah.

Also, 64-bit simply means you can use more of your memory for KSP so you can have more mods installed. Nothing else.

[Guest]

Intel, purely because its single thread speed is much faster - Intel definitely wins this one (not an Intel fanboy).

I would, however, suggest a dedicated video card - KSP is CPU reliant, however people forget that a graphics card does help too! Take a look at the new 750 series of cards from nVidia - they look great for this purpose - pretty cheap too.

[Barefoot Friar]

Thanks for the replies!

Since you've narrowed the choices down so much already, this is easy.

Do I need to expand my search a bit? I admit I've narrowed it down to those two by completely subjective and arbitrary means.

The Intel chip is going to be substantially better. More cores means nothing to KSP so the 8 core is not going to be better in any way, in fact it would probably be worse as Intel chips tend to be better per-core, which is why Intel chips cost much more than AMD ones that seem to be much superior.

Okay, this makes sense. So now the only reason I would want the 8-core chip is if I was running some other piece of software that would utilize it. Which I'm not, and doubt I ever will.

Also, the 4670K can be overclocked to well over 4.2 GHZ so if you are willing to overclock you are going to get substantially better performance.

The 4670 and the 4670K are identical, except the K can be overclocked. Is the 4670 faster than the AMD (for KSP purposes) even without overclocking?

Also, 64-bit simply means you can use more of your memory for KSP so you can have more mods installed. Nothing else.

Okay, that's worth the difference right there. I do use mods. I'm not a modhog, but my ideal setup is MechJeb, Kethane, Kerbal Alarm Clock, NovaPunch, and maybe one other parts mod (although I tend to pick and choose which parts I install). So having extra memory, especially since I will always have system resources running in the background, is a good thing.

Intel, purely because its single thread speed is much faster - Intel definitely wins this one (not an Intel fanboy).

I would, however, suggest a dedicated video card - KSP is CPU reliant, however people forget that a graphics card does help too! Take a look at the new 750 series of cards from nVidia - they look great for this purpose - pretty cheap too.

I shall do this.

[CalculusWarrior]

I'm running an i5-4670K right now and I love it. I just upgraded from a little laptop, and being able to play KSP with max settings is fantastic. I agree with the above; if price is irrelevant, go for it, as it will blow the AMD out of the water. An i7 won't improve your performance much, as ~4 GHz is about the fastest clock speed you can get a core to go at, so the higher end cores are more focused on multithreading, something the Unity engine is not very good at.

[Xaiier]

Do I need to expand my search a bit? I admit I've narrowed it down to those two by completely subjective and arbitrary means.

Not really, the i5 4670K is probably the best midrange chip you are going to be able to find, and it will work great with KSP, better than a lot of higher-end ones.

The 4670 and the 4670K are identical, except the K can be overclocked. Is the 4670 faster than the AMD (for KSP purposes) even without overclocking?

To be honest, I can't be entirely sure. As Linear said, theres subtle differences in single-thread speed and other things, so GHz isn't always a very accurate measure of performance. CalculusWarrior seems to have had success with it, and I probably will too as of tomorrow when I get my new machine built.

[_Aramchek_]

The Intel chip is miles more powerful in just about any and every application you'll use and it is light years ahead of the AMD chip in KSP.

I had a 8 core amd black cpu and it was overclocked, my i5 at stock speeds was faster than the amd system pushed to it's limits.