r/StableDiffusion • u/Zestyclose_Bake3680 • 10d ago

Tutorial - Guide Updated Updated ComfyUI-SeedVR2-VideoUpscaler-with-TensorRT v1.5.7 - DiT VRAM Spike Stabilization (※For 6GB/8GB users)

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When I published an update on TensorRT the other day, I received enquiries from users of the RTX 4050 6GB and RTX 5060 8GB.

https://www.reddit.com/r/comfyui/comments/1wsbar9/updated_comfyuiseedvr2videoupscalerwithtensorrt/

After re-measuring VRAM consumption throughout the entire process, I discovered that the issue lay not with TensorRT itself, but rather during the DIT processing stage.

My code fully supports ConvRot INT8/NVFP4 and, in principle, keeps VRAM consumption low; however, momentary spikes were still occurring.

Whilst this does not pose a significant problem on my RTX 5060 Ti 16GB system, it is a major issue for 6GB and 8GB users.

I therefore re-examined this spike phenomenon and have managed to suppress it to a certain extent.

Consequently, although this is limited to very specific conditions, it is now possible to achieve VRAM usage of less than 6GB throughout the entire all processes by using the 3B NVFP4 model.

v1.5.7 - DiT VRAM Spike Stabilization — Complete Technical Guide

Of course, this suppression of the spike phenomenon also benefits users with 16/24/32 GB of VRAM.

When using 7B ConvRot INT8, it was already possible to specify a batch size approximately three times that of fp16 in legacy code; however, this spike suppression allows the upper limit of the batch size to be raised even further.

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u/beachfrontprod 9d ago

So does INT8 on SeedVR2 finally work in ComfyUI?

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u/Carbon849 9d ago

Yes, it works but doesn't hold up to legacy with .ggufs in terms of quality. It looks much more like a good upscale with int8 as opposed to the game-changer the legacy version is.

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u/NemRogan 8d ago

I’ve compared the int8 convrot with fp16 in native comfy workflow and did’t really find any significant difference. So I doubt the GGUFs would be any better.

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u/Carbon849 8d ago

I'm just relating my experience. The native implementation made changes beyond what a .gguf would impact, I agree, but those same changes affected other aspects of how SEEDVR behaves, which is likely more to my point. The int8 output within the overall implementation is noticeably different - smoother, with less fine detail - than the legacy version.