Qwen3.8 27B vs Flash Next vs Qwen3.6
In the past few days, I have gained the following experiences:
Although the performance of the Qwen 3.8 27B model is not bad, but...
Let's start at the very beginning. In terms of raw computing performance, coding based on my local measurements and in practice, it seems that the Qwen3.6-27B-Q4_K++ models are almost on the same level as the Qwen3.8 27B model. The big difference is that the 3.8 thinks a lot. This is where its advantage comes into play. The tool calling is better, so it is more efficient overall. However, it is not necessarily smarter.
If I set the thinking value to med or min for the Qwen 3.8 27B instead of xhigh, it consistently underperforms in the tests compared to the Qwen 3.6 27B.
So Qwen 3.8 27B is only smarter if the reasoning level is xhigh, but then it is incredibly slow and generates a lot of tokens. And the worst thing is that even though the KV cache is Q8 quantized, it still requires a brutal amount of RAM/VRAM compared to Qwen 3.6.
And here comes the point that needs to be discussed.
Qwen 3.6 27B runs with 200k+ ctx on my 22 GB GPU in good quality.
Qwen 3.8 27B does not. This is not enough for it, there is a maximum of 100k ctx in the VRAM and the model is only Q4 quality, the KV cache Q8, because below it the model will be brutally stupid, a lobotomy. Obviously the best would be F16.
So I think that for planning and ideation, thinking, Qwen 3.8 27B is suitable, but for implementation 3.6 27B is perfect and MUCH faster. But...
This is where Qwen 3.8 Flash Next comes into play.
While on the 2080 Ti card (22GB Modded) on the i9-7980XE CPU with quad channel DDR4 (128GB) RAM:
the Qwen 3.8 27B model runs at Q4 quantum quality, ctx 100k, KV Q8 settings at approx. 35-45 t/s with MTP,
the Qwen 3.8 Flash Next (Qwen3.8-Flash-Next-GSQ-RCO-IQ3_XXS) with STRATA, ngram can easily fit on 1 GPU with 256k ctx (KV Q8) and 64 GB RAM is enough for it. The speed is currently 60-75 t/s and the strata is developing at full speed.
A fast SSD is probably also important for this, but I'm not sure, because I think the ngram table is in the RAM now. By the way, I only have Gen3 PCI-e ports, so I solved the SSD acceleration by connecting 2 average SSDs to nvme ports and creating an array with RAID0, and then their speed added up.
Experiences about the Qwen 3.8 FN:
It doesn't overthink things. It can think a lot, but not always, only when justified. It's precise, follows instructions, smart. I'll risk saying that based on my usage habits, it's smarter than the GLM 5.3 Flash.
Since its speed is also better and the VRAM requirement is less than the Qwen 3.8 27B, the question now is which model should I choose? I think the answer is clear.
Do you have similar experiences?