Deepseek v4 flash - 100-150 faster t/s in prefill/pp.

Reddit r/LocalLLaMA Tools

Summary

This post shares fixes to improve DeepSeek v4 Flash prefill/PP speed: downgrading CUDA from 13.3 to 13.1 or using a custom fork, achieving up to 1.3K prompt processing tokens/s.

You have two choices here (in order of pref): Downgrade CUDA from 13.3 to 13.1 (skip 13.2 due to bugs) <- prefer this (thanks to u/fairydreaming for pointing this out) Use this vibed fork that works with CUDA 13.3 https://github.com/vektorprime/working_ds4_speed I was troubleshooting this yesterday with the nvidia profiler and some LLM help (https://www.reddit.com/r/LocalLLaMA/comments/1vcs7bl/ds4_flash_full_model_in_offload_600_ts_pp_and/) Here's some more info on #1 (quote from fairydreaming) "Downgrade your CUDA and recompile. Starting with 13.2 DeviceTopK is used for top-k instead of argsort, this turns PP rate to crap." In short, DS4 Flash is spending a lot of time on things other than matrix multiplication. EDIT: Try this fork now because I can easily hit 1.3K prompt processing.
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