Best Qwen3.5 9B quant for a 8GB GPU

Short answer: Q5_K_M from bartowski . Of the 9 Qwen3.5 9B files we tested that fit fully in 8GB with a 8192-token context, it has the smallest diff from the BF16 model (mean KLD 0.0093, same top token 96.4%).

Smallest diff that fits 8GB
Q5_K_M by bartowski
File size
6.62 GB
KLD (mean)
0.0093
Same top token
96.4%
Tool calls
92.5%
Generation
88 t/s full GPU
Qwen_Qwen3.5-9B-Q5_K_M.gguf
Runner-up
UD-Q4_K_XL by unsloth
File size
5.56 GB
KLD (mean)
0.0206
Same top token
94.4%
Tool calls
90.5%
Generation
97 t/s full GPU
Qwen3.5-9B-UD-Q4_K_XL.gguf
Fastest that fits
UD-Q2_K_XL by unsloth
File size
3.84 GB
KLD (mean)
0.2071
Same top token
81.4%
Tool calls
82.0%
Generation
133 t/s full GPU
Qwen3.5-9B-UD-Q2_K_XL.gguf

Other budgets: 12GB16GB24GB ยท all 11 Qwen3.5 9B quants

How we picked

We estimate VRAM need as file size + f16 KV cache for 8192 tokens + about 0.6GB of compute buffers, and keep 0.5GB free for your desktop. Among files that fit, we rank by mean KL divergence against the BF16 model's logits, then by tool-call score. If you need a longer context, step down one quant level or quantize the KV cache (-ctk q8_0 -ctv q8_0). Methodology.

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