Could you shed some more light on the differences when you switch from Q4 to Q6_K? Tbh, I prefer having larger context windows since it looks like qwen just figures it out eventually. Since I noticed that it really wants to fill its context by, e.g., reading many files etc. I'd be open to experiment with smaller context windows and less quantization in my ninfer fork [0] if there's a benefit to it. But sometimes I think it's just more art that science :)
[0] https://github.com/tensorninja/ninfer-4090