Unleashing Blackwell's 4-bit: a surgical look at MXFP4 and NVFP4

If you do kernel-level inference optimization, you eventually hit the cold truth: the enemy is not compute, it is VRAM bandwidth. FP32 numbers are huge in memory. The fix is to squeeze them into 4-bit boxes. The internet is full of repos that do this. They say "find amax, divide by this, shift the bits, here is your FP4," and move on. I copied those formulas into my own code at first - and could…