Benchmarking vLLM vs SGLang vs llama.cpp on a mixed Blackwell/Ada cluster

The author benchmarked long-context prefill on a 7-GPU mixed Blackwell/Ada cluster; on Qwen3.5-397B-A17B with 75k tokens, vLLM reached 9.8s TTFT and 7,683 t/s, while llama.cpp took 57.2s and 1,319 t/s.

Why it matters: Single-source Reddit benchmark, so source authority keeps it near the threshold. HKR-H/K/R pass on the mixed 7-GPU setup, 397B at 75k tokens, and concrete TTFT/throughput numbers.