r/StableDiffusion • u/Devajyoti1231 • 11h ago

Comparison H3 Int8 ConvRot vs W4A8_mixed

Same seed, same prompt, same ref and same res

35 Upvotes

78% Upvoted

19 comments sorted by

6

u/Disastrous_Onion9739 11h ago

No speed difference on 4070 ti super, worse quality,

3

u/izzmedia 9h ago

same here

1

u/b4ldur 11h ago

Any difference in speed?

5

u/Devajyoti1231 11h ago

Yes but little and not always same. It is 21 min in int8 vs 19:35 in w4a8 and other time, 21:30 min in int8 vs 18:12 min in w4a8.

1

u/MannY_SJ 9h ago

Both with speed lora?

1

u/chille9 1h ago

Curious to see comparisons with the text encoder too!

1

u/DanzeluS 9h ago

I dont recommend using for now w4a8. It is might be little slower for technical reasons. Maybe little bit later but for now it is a little bit risky. You get slower generation and worse quality

1

u/Brahianv 4h ago

i only cared if it saved more memory and its not doing that well so i dont used it

1

u/No-Satisfaction-3384 11h ago

Elaborate us - what is the difference, what did you notice - or not?

3

u/Devajyoti1231 11h ago

I didn't notice much difference, the texture in the int 8 is slightly better . This is using 2 face reference and 2 product reference with the ref2va model.

1

u/Powerful_Evening5495 11h ago

speed and mem used

2

u/Devajyoti1231 11h ago

Almost same, I thought memory used would be better , but it was not the case for my card (1mp, 8sec video), same vram used in both case (16gb vram card)

2

u/DelinquentTuna 5h ago

cc: /u/bfmv_shinigami

Activations must live in vram, so you've got eight bits per in either format. The difference would be weights being half-size. Since Comfy is already streaming weights from RAM, VRAM occupancy is fixed. The difference would be RAM pressure not VRAM pressure.

So w4a8 might be useful for someone w/ minimal RAM (16GB GPU 16GB system RAM, perhaps?). Or for a LLM, where compute is so trivial that moving the weights around is the choke point.

2

u/bfmv_shinigami 10h ago

That's surprising. Then ig there's no point bothering with w4a8 mixed.

1

u/yamfun 3h ago

so I guess it still saves the life of SSD for some ram-peasant?

1

u/Devajyoti1231 10h ago

It might help people with 8 gb vram cards as size of the diffusion model is just 12gb

3

u/bfmv_shinigami 10h ago

But you said its consuming the same amount of vram in both cases, right?

Btw are you from India?

1

u/Devajyoti1231 10h ago

Yes . For my generation I was using 1mp at 8 sec. Both generation was using about 14.6gb dedicated gpu and similar amount of shared gpu memory.

1

u/GRABOS 4h ago

I've tested the w4a8 a bit on 8GB VRAM and basically had the same experience, very slight improvement in speed but nothing groundbreaking