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by turova 29 days ago
For qwen3.6-27b you can also run the q4 variant with full ~250K context on one 3090. It's fast enough to not be frustrating so the speed gains with 2x 3090s wouldn't be worth it to me. Running a q6 on 2x 3090s at half the speed with a smaller context is an option, but you're really not going to compete with SOTA models there anyway so unless you already have 2x 3090s, I would say 1 is the best investment given current prices. It's good enough to do a lot, especially with a well-configured harness.
2 comments

Are you running qwen3.6-27b on one 3090 with your KV cache at q4? Ime there is significant long-context recall accuracy degradation at that precision. I prefer putting the KV cache at q8 and working with the 120k context
Use modern samplers and you don’t need to limit yourself to 8bit at half the context window. I could push it down to 1.58 bits and get decently good output easily by simply not using the garbage default top_p and top_k that vendors continue to wrongly recommend.
Where do you find optimal samplers and sampler settings for these models? Very interested in this as I, too, use Q8.
That math (250k context, Q4 model, 24GB VRAM) only checks out at q4 quant for the K/V cache, which is probably not the best idea.