Modal Shows Mixed-Precision Samplers Across Six Accelerator Types Cut RL Cost ~15%

lmoroney · x · 2026-10-15

Modal's Nan Jiang and team trained Qwen3.6-35B-A3B on agentic coding with fully asynchronous RL, running samplers on six accelerator types (B200, B300, H100, H200, A100, RTX PRO 6000) at mixed precisions including NVFP4, FP8 and BF16, while a BF16 trainer ran on B200s. Off-policy corrections (score centering, masked importance sampling, top-p with mask replay) kept the mismatch bounded. On SWE-bench Pro V2 the mixed setup tracked the homogeneous B200 run with 15% lower sampler cost per update — significant since sampling already consumes 80–85% of GPUs in large RL runs.

Related event: Modal demonstrates stable, cheaper RL training on mixed-precision, mixed-accelerator clusters(7 posts)→

Original post →

More from Infra

Infra channel →