Threadripper or mainstream CPU with multiple GPU’s ?

[CTRL SPACE]

Hi,

As I’m currently in the process of gathering info for a new PC build, one question I have is the relevance of a multicore high-end CPU (Threadripper) vs a multi GPU setup on a more mainstream (and cheaper) CPU/motherboard with RTX 4090/5090’s etc. Some considerations:

V-ray GPU rendering becoming more advanced but still missing CPU functionalities – will this change to a complete similarity over time?

Project file size with large amounts of objects and materials, Forest Pack for major landscaping etc. – Performance on Threadripper CPU and its large amount of ram vs multi GPU on mainstream CPU (with a possible video ram bottleneck?).

Software multi thread functionality vs high single core clock speed.

Max possible number of large GPU’s on non-threadripper motherboard? PCI lanes and support/speed.

Cost of adding/upgrading GPU’s along the way vs CPU/motherboard.


So TLDR: Where does the Threadripper shine vs a mainstream CPU with multi GPU’s today or in 5 years time, - according to Chaos Group maybe?


Software being used for the above considerations:

3ds Max 2025 with Vray 6 and Forest Pack 9
Autocad Mechanical 2025
Revit 2025
Unreal 5.4 (or Vantage in future) for VR
QGIS - Rhino 7
Photoshop - Illustrator - Indesign


Thanks in advance for any input,

[glorybound]

Occasionally, I dip my toes into GPU and always find myself back in CPU. I purchased a second 4090, tried with GPU, and am still back in CPU. I would say invest in CPU power.

[Vizioen]

Depends on which type of projects that you're doing, if you're doing interiors and occasionally some small houses, or product visualization, then I would test if GPU is for you. I'm used to CPU (Threadripper) and 256GB of ram, which I occasionally almost fill up. Granted I could optimize my scenes a bit more to shave of maybe 20GB but that's not going to make a lot of difference on GPU and the time that I spend optimizing is the time that it's rendering. You have out of core memory, or shared memory between multiple GPUs (I think), but that slows things down apparently. You would also need a couple of good GPUs to be performant enough to match that of a threadripper on more heavy scenes. But GPU for some use cases is a lot faster, just not for mine, so it's up to you to decide which projects you do and if GPU is a better choice for them. I tested a (very) simple scene GPU (1 x 3080ti) vs my Threadripper 3990x and it didn't come close in performance.

You also have Vantage and soon Envision, which also run on GPU, so if you want to be able to use those, go for (multiple) GPUs. If not and you have big and heavy scenes like I do, go for CPU.

Vantage on my setups (threadripper 3970x + GTX2080Ti / threadripper 3990x + GTX3080Ti) is just too slow for me. You need multiple GPUs to make it behave nicely I find.

[CTRL SPACE]

Thanks for chiming in,

glorybound - is that an effect of lesser performance even on the two GPU's compared to your CPU, not enough video ram or missing functionalities?

Vizioen - My projects vary from small interior designs/scenography to large scale landscapes with Forest Pack, so a bit of both. Added to this is Unreal Engine (or Vantage at some point) for early development VR. - In this case I guess a best fit down the line would be a Threadripper (midrange?) with a fast GPU which can be expanded upon later (which is also easier on the TR motherboard)?

General question regarding GPU rendering: as I understand, the use of double the amount of GPU's of the same make see an almost double performance as long as your project fits into the ram of one of them..?

Thanks,

[seandunderdale]

Its been a long time since I used GPU, maybe things have changed...but I found I was bug fixing more than I was working. And once i switched back to CPU, sure there are still issues, but I work more than I bug fix...or should I say find workarounds for issues. No doubt people use it, and enjoy it, especially when you can just stack GPUs together and blast through renders. Lots of software does seem to skew to GPU power, but for my work, I just find I get stuff done fast, and reliably with CPU. Once AMD release a new 128 core (256 thread) CPU I'll upgrade from my 3990x.

[glorybound]

is that an effect of lesser performance even on the two GPU's compared to your CPU, not enough video ram or missing functionalities?

I have to switch to 2k materials, and Forest Pro seems to kill GPU performance. When it works, it works well—most of the time, I let my CPU run for an hour, with denoiser at something lime.4. I get results similar to those of my GPU. If you go by the est CPU render time, you might think the CPU is a joke, but again, after an hour, my renders are pretty clean.

[Morbid Angel]

I just ordered x2 AMD Ryzen Threadripper 7980X machines with 256GB of ram. I have been a cpu loyalist due to its reliability and versatility. These new cpus pack a ton of cores, these ones are not even top of the line. Top of the line tr5 would have 96 cores and cost $15k (CAD).

[haniel1107]

I just ordered x2 AMD Ryzen Threadripper 7980X machines with 256GB of ram. I have been a cpu loyalist due to its reliability and versatility. These new cpus pack a ton of cores, these ones are not even top of the line. Top of the line tr5 would have 96 cores and cost $15k (CAD).

Hi, may I ask, which CPU cooler are you using, or is it a complete PC?

[CTRL SPACE]

Morbid Angel - Sounds like a great team-up, - do you combine the two through any distributed setup? The reason for it being the 7980x's as opposed to the 7970x, - is that the doubling in cores (giving roughly 60-70% increase in rendering performance from what I can find) or some other general thoughts on the build if I may ask? And for the TRX50 quad ram in these sizes, would you recommend any specific brand from experience?

Thanks,

[Joelaff]

Been running a 7995wx with 512Gig for a few months now. Fully worth it for VRay work. The interactivity is so much better. Nuke runs better on the 7950x/9950x however (esp under Linux) because Nuke is an ancient, inefficient code base that does not scale well.

If you go the Threadripper route I would do at least 64 actual cores or you are likely better off with the 9950x. For most tasks we had better performance with a 7950x vs a 32 core 5975wx for instance. And the cost difference is substantial.

Of course the 7995wx seems to be around 3 or more times faster (typically about 3.2x) than the 7950x for pure rendering.

For pure rendering it is a no brainier to go ThreadRipper (though for a farm probably not because you can get far more nodes with cheaper cpus for the same price). If you do a lot of sims on the workstation I would go 9950x because the Threadrippers are typically no faster and often slower depending on the sim (we sim on the farm typically). If you get the right memory you can get up to 192Gb of 5000 MHz ram on the 9950x. That is generally plenty. I can look up the RAM we have if you need it. Or do a little research, but once you put a lot of RAM in those boards they become more finicky.

Every time I try GPU it is a major disappointment. Too many features don’t work right if at all things look different so you can’t just switch back and forth. And with a 7995wx the GPU speed advantage is no longer there, even using 4090s of course.

[Vizioen]

Been running a 7995wx with 512Gig for a few months now.

O waw, that setup is the price of a small car. Did you ever fill that 512? What do you do to need that much RAM?

[Joelaff]

Not to mention the $1600 UPS you need to run this, especially with PBO on, where it will pull ~1200W from the wall-- 1 KW just for the processor with PBO on. However, PBO is helpful for this processor because it lets the single threaded stuff run a lot faster, which of course is the majority of what computer do, other than rendering.

Well, Fusion was way more efficient as using a lot of RAM that Nuke (which will also use a decent amount). But when running two or three instances of Max and Fusion or Nuke, then it would get into the 450GB range sometimes.

512GB is almost definitely overkill without running something that uses gobs of RAM like a compositor, and even then is likely overkill. I had 512GB on my last box, and really didn't want to go back down.

Another way the huge amount of memory comes in handy is for those times when you bump a setting and Max eats up all your memory really quickly, bringing your machine to such a crawl that you have to force reboot (like bad displacement settings, etc., bump subdivions too high by accident, etc. You have way more time to notice this and kill Max before it locks up the system

The processor, on the other hand, is freaking amazing for VRay... like I say usually over 3x faster than a 7950x (assuming it's not a render that doesn't thread well). With that much RAM and processor you can also run multiple instances of programs when rendering and max things out that way. Doing that you can make even poorly threaded Nuke perform decently if you have enough frames at once.

Also, I think when I ordered this the modules for 256Gb were out of stock, and 128Gb is definitely too low. I don't regret the processor purchase at all. The RAM is probably not worth the extra $$ beyond 256Gb.

[Morbid Angel]

Hi, may I ask, which CPU cooler are you using, or is it a complete PC?

The shop has quoted this cooler, said it works well (I guess we will find out)
Noctua NH-U9 TR4-SP3 CPU cooler

[Morbid Angel]

Morbid Angel - Sounds like a great team-up, - do you combine the two through any distributed setup? The reason for it being the 7980x's as opposed to the 7970x, - is that the doubling in cores (giving roughly 60-70% increase in rendering performance from what I can find) or some other general thoughts on the build if I may ask? And for the TRX50 quad ram in these sizes, would you recommend any specific brand from experience?

Thanks,

These machines are going to be used mostly as simulation nodes with capability of workstations of course as well. We typically don't do distributed rendering (only in rare cases). I found that 7980 is a good price for what we get. I need two of those so buying top end cpus would bring the cost to around $30k. We have a large render farm available so most of the frames are rendered on those machines and for rack space density 4u single cpu with many cores is highly advantageous.

[haniel1107]

The shop has quoted this cooler, said it works well (I guess we will find out)
Noctua NH-U9 TR4-SP3 CPU cooler

Hi Morbid Angel-, this helps me in planning a new pc. thanks a lot..!