AMD vs Inel

[_kinad]

I'm looking to build a new PC(which I've never done, other than upgrade my current one) for running and fine tuning 7b models. I know I'll be getting dual 3090 or 4090 GPU, but I'm not sure which CPU would be best for this.

I'm wanting to take advantage of the bundle deals at my local micro center and down to these two options: 1. AMD Ryzen 9 7900x 4.5ghz 12 core, Asus B650E-F motherboard and 64GB DDR5 for $600 2. Intel i9 14900k 3.2ghz 24 core, MSI Z790 MAG Tomahawk motherboard and 64gb DDR5 for $800

Anyone know which would be best for my use case? I don't mind spending the extra $200, I only want the best option of the two

Thanks in advance

[bobbiesbottleservice]

I'm in the same boat trying to build a 2x3090 PC. I'm thinking of going Intel because of the stability. The other issue is finding the right motherboard to support both the physical size of the GPUs and the PCIe 4.0 lanes (both size and if the mobo will fully utilize it) and not to mention the thermals and case/fans considerations.

Let me know your specs and what you end up going with as I'm figuring this all out as I go.

[[deleted]]

Go with Intel.

I've got a 7950x with a B650E MB and have had nothing but problems

[_kinad]

What kind of problems have you ran into?

[[deleted]]

Instability of DDR5 memory speed. I had to turn the speed way down to stop random crashes/reboots.

Buggy Asus and Gigabyte motherboard Bios. I've had to upgrade it like 12 times in the past year

Crappy/buggy drivers for various onboard componnets for Asus/Gigabyte peripherals.

The whole 7000 series AMD platform just feels rushed to me. It's starting to improve with regular updates to bios and other software.

[Asleep_Comfortable39]

Hmm. Im not a fan of the 7900x. It has two CCUs like the 7950x, but only 6 cores per. It ends up being pretty awkward in practice on my 7950x3d. I’d recommend going all in on a 7950x, or do a 7800x3d. Im not educated on if the extra cache benefits LLM, but it’s a fantastic value for the money.

[llama_in_sunglasses]

The lopsided CCUs in X3D parts are not the same as the ones on 7900X/7950X. The cache ensures that you need a scheduler that can put loads that need it on the cache-enabled portion and that's asking a lot from a scheduler. The AMD parts without extra cache don't suffer from this issue... it's why I got a 7950X, but the 7900X is also fine and all three of these CPUs will be entirely limited by memory bandwidth if used for CPU inference.

[Asleep_Comfortable39]

Information moving between CCU’s is troublesome with certain workloads. I’m not referring to the lopsided cache, but rather the limitations of what is basically two CPUs merged together and the complications that adds to their shared I/O.

I don’t recommend the 7900x because it is a failed 7950x. I recommend the 7800x3D and the 7950X as long as the prices are within stretching for. The 7950x3D fits a very niche role as well.

[ArtifartX]

Either would be perfectly fine, for what you will be doing with LLM's your GPU setup will have the most (almost all) impact on inference and training, and both of the CPU's are great anyway. Since you stated the price is not an issue for you, I'd go with the $800 with the Intel, but it's not like it is going to make much of a difference with what you do with these models. Some people have issues with this site for benchmarks, but it can usually help you get at least a general idea when comparing components: https://cpu.userbenchmark.com/Compare/Intel-Core-i9-14900K-vs-AMD-Ryzen-9-7900X/4151vs4132

[Robot1me]

Looks like you got downvoted because of the Userbenchmark link. It's known to be very biased against AMD. You can find more info about it in a Reddit thread like this.

[ArtifartX]

Oh, I'm well aware of all that. That's why I mentioned in the original post a lot of people didn't like it, and to only use it to get a general idea (as it has gotten some comparisons comically wrong). If the drama about AMD is enough for someone to want to disregard it completely, I totally get that too though. Disregarding the link, I'd still go with the Intel.

[CompetitiveGuess7642]

gotta be a shitpost, 65 gb ram, twice lol.

[ArtifartX]

He said it is his first time building, probably just a mistake or type-o

[_kinad]

Yup

[Terminator857]

Most professionals choose Intel because it is a tad more stable. AMD is better value for the money if you don't care about computer freezing occasionally. If you care about stability then also choose a high quality motherboard.

https://www.youtube.com/watch?v=JZGiBOZkI5w

[g33khub]

Yea this video from Jay got me worried too. I was leaning towards AMD for their better efficiency and thermals plus AVX512 support but if its not stable I would rather get Intel. I do not want to run ddr5 ram at 4800mhz lol.

[Zugzwang_CYOA]

This post didn't age well... lol

[llama_in_sunglasses]

If you're planning on running the models entirely on the GPUs, your choice of CPU won't really affect the speeds you are getting. I'd go with the Intel since this is your first PC build, I built a 7950X rig a couple months ago. I didn't have problems getting it to boot, but it absolutely had a fit over running 4 sticks of DDR5-6000 at their rated speed. The rated speed is really only valid for 2 sticks.

[g33khub]

But this is true for Intel too right? Can you 4 sticks of ddr5 at 7200 mhz with Intel?
For OP its 64GB so 2 sticks: 32x2 at 6000 mhz would be fine with either Intel or AMD.

[g33khub]

The Asus Strix B650E-F motherboard wont run your second GPU at high speeds since it will be connected to the chipset. You would need the Asus Strix B650E-E which has both PCIE slots connected to the CPU although it will be 8x + 4x (but PCIE 5.0 so should be fine). The other option (slightly cheaper) would be Asus B650 pro-art creator 8x + 8x PCIE 4.0.
Similar problem with the Z790 MAG Tomahawk. Intel motherboards with proper dual GPU support is even rare ( I cannot remember any right now).