Can RX 7900 XT 20GB run Qwen3.5-27B?

AMD · 20 GB GDDR6 · 800 GB/s bandwidth · Alibaba · 27.0B · model ctx up to 256K

Partly — Qwen3.5-27B at Q4 fits the RX 7900 XT 20GB (20 GB GDDR6) at 4K context (≈ 18.55 GB) but not at the default 8K (≈ 21.25 GB needed). Use a shorter context or partial offload. Decode at Q4/8K: ≈ 47.7 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	18.9 est.
Q4	8K default	21.25 GB	No	47.7 est.
Q4	32K	37.45 GB	No	15.4 est.
FP16	4K	57.7 GB	No	1.8 est.
FP16	8K default	60.4 GB	No	1.6 est.
FP16	32K	76.6 GB	No	1.0 est.

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).

VRAM breakdown at 8K context

Quant	Weights	KV cache	Overhead	Total needed	RX 7900 XT 20GB VRAM
Q4	14.85 GB	5.4 GB	1 GB	21.25 GB	20 GB
FP16	54.0 GB	5.4 GB	1 GB	60.4 GB	20 GB

Other GPUs that run Qwen3.5-27B

• B200 192GB SXM — ≈188.6 tok/s Q4 est.
• MI300X 192GB — ≈124.9 tok/s Q4 est.
• H200 141GB SXM5 — ≈113.1 tok/s Q4 est.
• H100 80GB SXM5 — ≈79.0 tok/s Q4 est.
• Gaudi 3 128GB — ≈77.2 tok/s Q4 est.
• A100 80GB SXM4 — ≈48.1 tok/s Q4 est.
• RTX 5090 32GB — ≈42.2 tok/s Q4 est.
• RTX 4090 24GB — ≈23.8 tok/s Q4 est.

All GPUs for Qwen3.5-27B →

Other models for the RX 7900 XT 20GB

• MiniCPM5-1B — ≈471.4 tok/s Q4 est.
• Qwen3.5-2B — ≈254.5 tok/s Q4 est.
• GLM-4.7-Flash — ≈169.7 tok/s Q4 est.
• Qwen3-30B-A3B-Instruct-2507 — ≈169.7 tok/s Q4 est.
• Nemotron-3-Nano-Omni-30B-A3B-Reasoning-BF16 — ≈169.7 tok/s Q4 est.
• gpt-oss-20b — ≈141.4 tok/s Q4 est.
• gemma-4-26B-A4B-it — ≈134.0 tok/s Q4 est.
• Llama-3.2-3B-Instruct — ≈131.2 tok/s Q4 measured

All models on the RX 7900 XT 20GB →