Qwen3.8-27B Quantization Benchmark: Q4_K_M Is Free, Q2 Costs 5 Points on Agentic Coding, 1-Bit Collapses to Random Chance
Quesma blog, via r/LocalLLaMA·medium signal
A Quesma benchmark posted 2026-08-26 ran Qwen3.8-27B across GPQA Diamond, IFBench, and Terminal-Bench 2.1 (89 agentic coding tasks) on L40S, H100 and H200 via Modal. Q4_K_M at 17 GB matched BF16 at 55 GB within a point on all three. UD-Q2_K_XL at 10.7 GB held instruction-following but dropped Terminal-Bench from ~77% to ~72%. Both 1-bit quants (6.2 GB) fell to 15-20% on GPQA Diamond, which is around random chance, and degraded further on longer reasoning.