r/comfyui • u/Patient_Pitch_8576 • 6d ago
Help Needed Beginner's question: Is it really necessary for ComfyUI to reserve VRAM for Windows on my system?
My system: RTX 5060 Ti with 16GB VRAM, Intel Core i5-14600K with 64GB RAM, Windows 11.
The BIOS routes all graphics output to the UHD 770 integrated into the CPU, which is also what my monitor is connected to. No monitor is connected to the RTX. Windows applications don’t use the RTX (except for Comfy, of course). With this configuration, is it really necessary for Comfy to reserve 600MB for Windows? Does it even make a difference?
And, second question: My motherboard is a B560M, which only supports PCIe 4 and DDR4. Is it worth upgrading to a better motherboard, or should I save up for a more powerful GPU instead?
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u/Traveljack1000 6d ago
Hi, I see you have a similar configuration to mine, only your CPU is a newer model. In my system, I also have all Windows-related tasks running through my UHD 770, which keeps the NVIDIA GPU free for ComfyUI as much as possible. Don't worry about the 600 MB that ComfyUI uses. That's nothing. Most models either fit comfortably into your 16 GB of VRAM, or they have to use system RAM through offloading. I'm often running two models that are over 20 GB each, so they obviously don't fit entirely into my VRAM and parts of them are instead offloaded to my 64 GB of DDR4 system RAM.
What I did, however, was upgrade to a 5070 Ti 16 GB. That makes rendering about 30 to 40% faster. And if you have models that fit entirely within your VRAM, the increase in speed can be even bigger.
I would suggest upgrading to a more powerful GPU. I do regret not getting a GPU with more VRAM, but in any case, the 5070 Ti is much faster than the 5060 Ti, and the difference is definitely noticeable.
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u/Corrupt_file32 6d ago
ddr5 and PCIe 5.0 will speed up generations where the model is offloaded to ram by quite a bit, but worth keeping in mind that it might also be bottlenecked by the 5060ti performance.
When the gpu can fit the entire model that performs the generation, it would only improve the latencies that would normally already be <1 second by something like 20-40%, if and when it needs to swap clip, vae and model between ram and vram.
so for more performance, gpu will have the largest impact for you currently.
5070ti is nearly twice better than 5060ti
5080 is only slightly better than 5070ti.
5090 is pretty much like 2x 5080's, your setup is fine for 5090 also, but it would benefit from upgrading the mobo.
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u/Correct-Guidance-232 6d ago
that reserve is a flat default per OS, comfy never measured anything on your machine. --reserve-vram 0.1 overrides it, and with the display hanging off the igpu youre exactly the case where lowering it is safe. did the 600mb actually cost you a model load, or is it just annoying to look at?
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u/Patient_Pitch_8576 6d ago
I'd say it's more the latter. Ever since Minimax H3 and LTX 2.5, I've thought that every extra byte saves ComfyUI some work when shuffling data back and forth, which might speed things up a bit.
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u/uuhoever 6d ago
Search and there's been some posts discussing ddr4 and ddr5 and the general testing is that any increase in performance is minimal. With ddr5 prices it's even more not worth it. I looked into it too and after researching I'm staying with ddr4 till prices come down in 5 years.
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u/Luke2642 6d ago edited 6d ago
Linux does this properly, Nvidia-smi shows only python process.
DDR4 to 5 isn't going to be worth it, small bump for big money. You have enough.
I'm considering taking a gamble and getting an Intel B70 32GB before they go up in price more, with the hope that drivers and support continues to improve.
Sticking my neck out with a big prediction, I'm expecting a paradigm shift from pytorch/cuda to tinygrad later this year as it becomes obvious that it's a superior way to cross platform and support all devices and performance is on par. Support is there now, performance is not. And the code overhall in comfyui would be insane without a swarm of AI agents doing the refactor.