My apologies for what will be very rudimentary questions. Yes, I have searched, but the conversations go way out of my wheelhouse by reply 2…
My purpose is specifically in speeding up rendering times, Blender 4.1 .Cycles engine. Windows OS. Budget: NOT unlimited. In fact I just do this for fun, so older stuff, not the best is all OK with me. If its takes a long time, but is a bit better, that is just fine My questions relate to hardware only.
I believe two (or more) video cards can be used which Blender can ulitise in GPU render, correct?
Some video cards don’t even seem to have videos outs (for monitors). Since I don’t need a monitor out, is this a good route take? Good " older" options (not BEST…ie Not $$$$$)?
If the PC has sufficient power supply, space, slots, would most cards work in most modern machines? ( I’m talking generalities here so am not including specifics).
If my machine has an Nvidia card (GeForce GTX745), the second also has to be Nvidia, correct?
Thanks for any clarifications.
I will say I tried Blender for awhile about 10 years ago. The program has come a long ways
Ehhh… kind of, but your CPU will bottleneck them and you’ll only get to use the VRAM of the smallest. Two GPUs is a huge waste, get one good one
See above.
Not at all. You can get a last generation 3060 for 300 dollars. There’s no point in getting anything lower than a 2xxx generation at this point, it’s just throwing away money when much better cards are so cheap
Correct, but there are a whole bunch of big if’s, but’s and maybe’s around that.
Again, correct, those are usually data center/compute type GPU’s. Anything new will likely be way expensive, while anything old enough to be affordable, is likely to get smashed by any current Nvidia RTX card for much the same cost.
Pretty much. It’s all based on PCIe slots and those have been fairly standard for past couple of decades.
Mixing GPU/drivers and the like, is in theory possible, but a very very bad idea.
Having said that, it doesn’t matter, that GTX 745 is so old, that from a Blender point of view, it’s e-waste.
To make Cycles rendering faster, you get pretty much any Nvidia RTX card (the most recent one you can afford) and you pull out the GTX 745, put in the new card and will be 1000% amazed at how much faster rendering is.
My only minor concern, is depending on what you are doing and if the rest of the system is the same age as the GTX 745, then while putting in a new GPU will sure help, it would also very likely be held back by any aging CPU/RAM, etc.
Do you have any sources or personal experience to back that claim? I’ve run 3 different multi-gpu setups at this point. After Cycles-X happened the performance scaling is pretty much linear and the 10 minute render on 1 GPU will render in 5 min on 2 GPUs. Again - I tested this myself. As far as I remember the problems start if you have more than 4 GPUs, but I’ve never run that kind of setup, so I cannot tell.
That is factually correct. The best option is to run 2 or more identical cards.
Nonsense. Render farms use multi GPU on a daily basis. If it wasn’t profitable or render slower than with 1 GPU per motherboard they wouldn’t even bother. With linear performance scaling in a home setup 2x4070ti will render same frame faster than one 4090 as long as the scene can fit into VRAM.
I think your bias is showing as EEVEE does not support multi-GPU rendering at all.
That said @WilliamM your GPU is so old that no matter how many more identical ones you buy they wont even get close to one modern lower-midrange GPU if we talk about performance. Beside that GPU has 2GB of VRAM which is the lowest VRAM capacity Blender supports. This puts a hard limit on what scenes you can make.
Two cards can give better performance than one, although that only really works if the cards are similar (or identical) and the performance gain may be limited by my CPU.
Adding a second card like I have would give a “Blender benchmark” of ~100 (50x2) which would be paltry in light of single better cards which could be in the 4000s.
Nice video cards are not $ thousands, but hundreds.
Not mentioned here, but it seems there is also the concern of the power supply requirements. It seems some of these video cards require some serious juice.
Video card slots seem pretty standardized.
RE:1 Mixing different GPUs should work in theory, but I personally never tested it. The most important aspect is VRAM size. GPU with the lowest VRAM capacity will limit scene size that can be uploaded to all GPUs in your setup. Once the VRAM limit is reached Cycles will switch to out-of-core rendering and the performance will drop significantly.
Slow CPU will bottleneck everything including modeling, geometry nodes, sculpting, etc, but also - render pre-processing and multi-GPU synchronization. If you have relatively modern CPU - say from Intel 9th gen or Zen 2 from AMD onward you should be fine. Newer CPUs will be faster - obviously.
RE:2 Pretty much.
RE:3 There are no bad products only bad prices. If you want to go deeper you can do some simple perf/$ calculations with numbers from Blender OpenData.
RE:4 I wouldn’t cheap out on a PSU.
You can go as fancy as OCP Accelerator Module standard, but it is still PCIe in the end.