Just like I did with my Faster Qwen3.5 122B, I’m basically doing the same with this great awesome new model from Qwen.
Single-line command:
git clone https://github.com/azampatti/Qwen3.8-Flash-Next-Int4-FAST.git && cd Qwen3.8-Flash-Next-Int4-FAST && bash setup.sh
Repos:
- https://github.com/azampatti/Qwen3.8-Flash-Next-Int4-FAST/blob/main/README.md
- azampatti/Qwen3.8-Flash-Next-125B-A5B-INT4-AutoRound · Hugging Face
Speed:
Of course ‘it depends’ but in my tests, between 60-70 tok/s in coding.
Context:
From vLLM’s launcher: GPU KV cache size: 644,732 tokens, Maximum concurrency for 262,144 tokens per request: 2.46x
But HOW?
I halved how many experts the model uses per token, from 10 to 5, then taught its shared experts to make up the difference by imitating the uncut model. Nothing was removed from the model. All 512 experts are still there, I just changed how many of them each token is routed to, which cuts active parameters from 6B to 4.8B and makes it faster, then healed the quality loss by training one small always-on component, 37.75M parameters with everything else frozen, to match the original’s output distribution and quality as close as possible.
MTP Draft head stays in BF16 and Topk10 to predict at the best possible quality with a tiny bit of speed penalty
Try it, enjoy and please provide me with feedback! I’m still improving this model every day, so I will be updating this thread when an improvement is posted.
What’s Next?
- I’m testing new containers as more talented people are working on them. That’s why I wanted to push this model through HuggignFace as well Just make sure you also pay attention to the launch parameters I use to ensure the best performance.
- Quality should be within 2% of the original 4bits models (both NVFP4 and INT4 I tried scored closely from each other), but I’m testing avenues to raise the quality even further like I was able to do with 122B. It’s MUCH harder with this model though , but I’m on it!
- Bookmark this thread, hopefully I can do at least weekly updates with improvements for the next couple of weeks. The idea would be to re-run the one-liner and that would check and update everything.
-Aldo
EDIT: IMPORTANT - The default chat template for this model thinks in EXTRA HIGH. I attached two slightly modified chat templates that are xhigh and medium but with some tweaks to attack some scenarios for stronger coding in OpenCode. I did not included them by default to avoid “cheating” on comparisons, but consider using the “medium” chat template, it’s faster and stronger, but benchmark it on default.
EDIT2: Up to 70tok/s Qwen3.8-Flash-Next-Int4-AutoRound - #13 by ds2atc @ds2atc benchmarked with tool-eval-bench and I’ve just personally validated in my DGX that this results are accurate.

