NVIDIA · 24 GB GDDR6X · 1008 GB/s bandwidth ·
Alibaba · 27.0B · model ctx up to 256K
Yes — the RTX 4090 24GB (24 GB GDDR6X) can run Qwen3.5-27B. At Q4 with the default 8K context it needs ≈ 21.25 GB VRAM (weights 14.85 GB + KV cache 5.4 GB + 1 GB runtime overhead), which fits within 24 GB. Decode at Q4/8K: ≈ 23.8 tok/s (estimated, batch 1). FP16 needs ≈ 60.4 GB — does not fit on this card. Estimates come from memory-bandwidth math; rows tagged measured override estimates. Relative ranking is more reliable than absolute tok/s. Methodology.
Fit & speed by quant and context
Quant
Context
VRAM needed
Fits?
tok/s (decode)
Q4
4K
18.55 GB
Yes
23.8est.
Q4
8K default
21.25 GB
Yes
23.8est.
Q4
32K
37.45 GB
No
27.9est.
FP16
4K
57.7 GB
No
3.2est.
FP16
8K default
60.4 GB
No
2.9est.
FP16
32K
76.6 GB
No
1.8est.
Fits = weights + KV(ctx) + 1 GB overhead ≤ 95% of VRAM. Measured
anchors are context-agnostic; the fit verdict is recomputed per context. A missing tok/s
means the model is far beyond this card (offload-only territory).