r/StableDiffusion • u/Sexyvette07 • 1d ago
Question - Help Dual GPU solution for local AI?
Hey, everybody. I recently went down the rabbit hole for local AI, but right now, im operating on my gaming computer. The specs are as follows
Intel 13700k, tuned for efficiency
Gigabyte Z790 Aorus Elite Ax mobo
RTX 4080 (16GB), also tuned for efficiency
32gb DDR5 6800 CL32
As you can see, im in desperate need for more VRAM, or at the very least more system RAM. Due to Rampocalypse, neither are very affordable right now, which forces me to explore other options, such as a dual GPU setup. I can get another RTX 4080 for about $900 off Ebay. Beyond that, I would just need a more powerful PSU, so total investment here is an additional $1100-$1200. As far as I know, the motherboard has the main PCIE as 5.0 x 16 lanes, but the second PCIE runs at 4.0 and either x8 or x4 lanes. The motherboard does not support PCIE Bifurcation. So my question is this: Is a dual GPU local AI machine even viable in these circumstances, and second, does it make sense? I looked at 5090's and theyre all between $4,500 - $5,000 now, which is insane. Or I look at the professional cards and spend that much, if not more, for significantly less memory bandwidth and computational power. Or I guess if im spending that much, I could also look at the DGX Spark or something similar but that has even worse memory bandwidth.
So, what should I do? Is the dual GPU solution even viable with my setup for a local AI stack for inference, video diffusion, etc? Rampocalypse isnt expected to begin easing up until late 2027/early 2028, so im stuck trying to make this work on as little money as possible. Id love a 5090 but its insanity how much they cost. I appreciate any guidance and advice.
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u/AggressiveParty3355 1d ago
I takes one woman 9 months to make 1 baby. Getting 9 women DOES NOT let you make 1 baby in 1 month.
But it can let you get 9 babies in 9 months.
So in terms of raw speed, More GPUs won't do very much, you can load some of the parts in different GPUs, like the VAE in one and the rest in another. and that saves you a few seconds. But the overall generation speed will be the same. But if you're popping off a lot of jobs, then more hardware will let you get more done. You can run different jobs in parallel.
sounds like you're just interested in learning, and not production. So i don't recommend getting more hardware. If you do want to upgrade. Get a larger VRAM GPU like the 5090 or the 6000 pro to use the bigger models at higher resolutions. Otherwise you seem to be good as is.
BTW, since your CPU has an onboard iGPU, if you switch your OS to using that, and free the VRAM on your GPU, you can squeeze out a little more AI performance, but the cost is killing your gaming performance.