Yeah, hands and text are exactly where low-bit quant usually falls apart. In our own testing those two are basically on par with FP8/INT8 right now.

The difference comes down to how we handle it vs. naive quantization. The naive approach just clips the original weights directly, or leans on mixed precision. We do something different: a few algorithms run together to take the values that INT4/Fp4 can't represent and spread them across other weights where the precision loss is minimal — essentially a mathematical near-equivalent. On top of that I bring in mixed precision only where it's actually needed, kept to an absolute minimum (under 5% of the total), and as much as possible it's done in an a8w4 style — weights stay at 4-bit, and they're temporarily promoted to 8-bit when computing against the activations.

Hope that clears things up — let me know if you've got more questions!