Qwen3.8 27B

User reports Qwen3.8 27B at 173 to 179 t/s decode on an RTX 5090, with 0.79s first token at about 8K prompt and four concurrent workflows done in 8.15s. Setup is vLLM with NVFP4 weights, fp8 KV cache, 262,144 context, MTP speculative decoding with 3 tokens, PIECEWISE cudagraphs, and prefix caching. The same 27B family also runs on a Radeon AI PRO R9700 32GB via Radiance in MXFP4 at 71 to 73 t/s decode, and on the 5090 via ExLlamaV3 at 40 to 70 t/s decode and 600 to 1400 t/s prefill at full 262K depth.