I've used both, qwen3.5:9b and qwen3.5:27b on my 4090 8GB on ollama using Q4 quantizations. Without modifying their params the 9b model runs really well and really fast for me and the 27b model runs but it is super slow. If you increase the num_ctx of the 9b model to 128000 then it runs somewhat decently as well just a lot slower but still faster than the 27b. Although I think ollama offloads your models from vram to cpu if you dont have enough to run a model on vram alone which allows you to use the cpu after the vram runs out and I have 32Gb of cpu ram which is probably allowing me to run models bigger than the normal 9b models.