Match each GPU generation to the quantization format that lights up its native tensor cores.
Hopper's native floor is FP8; Blackwell adds FP4 on top. INT4-weight (AWQ/GPTQ) is portable; W8A8 is pre-Hopper; BF16 is the reference baseline.
Each new GPU generation lowers the floor of what numbers it can multiply natively. The older generation could only count down to a certain precision before it had to fake it. The new generation introduces a smaller, faster unit. Picking the right floor for your hardware is like picking the right gear in a car. Too high a gear and the engine bogs down, too low and you redline. FP8 is the right gear for Hopper. FP4 is the right gear for Blackwell. Using FP8 on Blackwell is like driving in third when fourth would be smoother. Using FP4 on Hopper does not work at all because there is no native FP4 unit, so the GPU has to simulate it slowly.
Detailed answer & concept explanation~6 min readEverything you need to truly understand this topic: intuition, mechanics, step by step explanation, code, formulas, and worked example. Click to expand.
Everything you need to truly understand this topic: intuition, mechanics, step by step explanation, code, formulas, and worked example. Click to expand.
Everything you need to truly understand this topic: intuition, mechanics, step by step explanation, code, formulas, and worked example.
Everything important, quickly.
5 min: walk the generational floor pattern from Hopper (FP8) to Blackwell (FP4), distinguish E4M3 from E5M2, explain W4A16 portability, contrast W8A8 against FP8 on H100, and close with the practical hardware-driven decision rule.
Real products, models, and research that use this idea.
- Llama 4 Maverick on H200 ships with native FP8 weights via the Transformer Engine for production serving.
- DeepSeek V4 serving on H100 uses FP8 W8A8 with custom kernels for further throughput gains.
- Anthropic Claude Opus 4.7 and OpenAI GPT-5.5 are widely understood to use FP8 in production on Hopper-class clusters.
- NVIDIA's TensorRT-LLM v0.12+ ships a turnkey FP4 path for B200 inference, including MX-FP4 micro-scaling support.
- Hugging Face's Marlin kernels enable W4A16 (INT4 weight, FP16 activation) on H100 for cost-sensitive deployments needing weight portability.
What an interviewer would ask next. Try answering before peeking at the approach.
QHow does the Transformer Engine pick per-tensor scale factors for FP8?
QWhy does Blackwell's FP4 require micro-scaling (MX-FP4) rather than per-tensor scaling like FP8?
Don't say thisRed flags and common mistakes that signal junior thinking. Click to expand.
Red flags and common mistakes that signal junior thinking. Click to expand.
Picking the same quantization for every GPU generation. FP8 on Blackwell wastes throughput; FP4 on Hopper has no native path; W8A8 on H100 underperforms FP8.
The night-before-the-interview bullets. Scan these on the way to the call.
Same topic, related formats. Practice these next.