Home / Can I run it? / gpt-oss-20b / gpt-oss-20b on an RTX 3080

No. gpt-oss-20b at Q4_K_M needs about 15.6 GB, and the GeForce RTX 3080 10GB has 10.0 GB usable at a ~4k context.

Can I run gpt-oss-20b on an RTX 3080?

gpt-oss-20b at Q4_K_M needs about 15.6 GB, and the GeForce RTX 3080 10GB has 10.0 GB usable. That figure is 10 GB of VRAM on the spec sheet, of which 10.0 GB is usable for weights and cache, at 760 GB/s memory bandwidth. OpenAI’s open 20B-class gpt-oss model. Only a few billion parameters are active per token, so decode can be quicker than a dense 20B. These are estimates from our formula, not measured benchmarks.

Quant that fits

None of Q4, Q8 or FP16 needs 15.6 GB

Memory needed

15.6 GB at Q4_K_M, ~4k context

Usable VRAM

10.0 GB of 10 GB VRAM

Est. tokens/sec

n/a does not fit

gpt-oss-20b · GeForce RTX 3080 10GB · Everything this machine runs · Q4 vs Q8 vs FP16

Memory at each quant

Estimated tokens per second

No speed estimate: gpt-oss-20b does not fit in the 10.0 GB this machine can use, so we do not publish a tokens/sec figure for CPU offload.

Context headroom

Even at a short ~4k context, the weights do not fit. Extending context would only increase the gap.

From the model’s config. Try other sizes in the VRAM calculator or see the context length guide.

What to do instead

• Run Gemma 3 12B instead (9.5 GB at Q4). It is a different model, not a drop-in, but it does fit this machine.
• To hold gpt-oss-20b at Q4, you need about 15.6 GB. The GeForce RTX 4060 Ti 16GB has 16.0 GB usable ($499 list price).
• CPU offload can load the weights anyway, but it is slow. We do not publish an offload tokens/sec figure.
• See the best GPU for this model family and the gpt-oss-20b model page.

Other hardware for gpt-oss-20b

• gpt-oss-20b on an RTX 3060 12GBWon’t fit
• gpt-oss-20b on an RTX 3070 TiWon’t fit
• gpt-oss-20b on an RTX 3090Fits
• gpt-oss-20b on an RTX 4060 Ti 16GBTight
• gpt-oss-20b on an RTX 4070 Ti SuperTight
• gpt-oss-20b on an RTX 4090Fits

Other models on an RTX 3080

• Qwen3-32B on an RTX 3080Won’t fit
• Qwen3-30B-A3B on an RTX 3080Won’t fit
• Qwen3.8-27B on an RTX 3080Won’t fit
• Gemma 3 27B on an RTX 3080Won’t fit
• Gemma 4 31B on an RTX 3080Won’t fit
• Mistral Small 24B on an RTX 3080Won’t fit