# Can I run gpt-oss-20b on an RTX 3080? | What Can I Run AI?

> No. gpt-oss-20b needs about 15.6 GB at Q4_K_M, and RTX 3080 has 10.0 GB usable. What to run instead.

Source: https://whatcanirunai.vercel.app/can-i-run/gpt-oss-20b/rtx-3080-10gb/

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**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](https://whatcanirunai.vercel.app/method/), 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](https://whatcanirunai.vercel.app/models/gpt-oss-20b/) · [GeForce RTX 3080 10GB](https://whatcanirunai.vercel.app/hardware/rtx-3080-10gb/) · [Everything this machine runs](https://whatcanirunai.vercel.app/what-can-i-run/rtx-3080-10gb/) · [Q4 vs Q8 vs FP16](https://whatcanirunai.vercel.app/quantization/)

## Memory at each quant

| Quant    | Need vs 10.0 GB | Verdict       |
| -------- | --------------- | ------------- |
| Q4\_K\_M | 15.6 GB         | Q4Won’t fit   |
| Q8\_0    | 26.6 GB         | Q8Won’t fit   |
| FP16     | 49.1 GB         | FP16Won’t fit |

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No speed estimate: gpt-oss-20b does not fit in the 10.0 GB this machine can use, so we do not publish a tokens/sec figure for CPU offload.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

__Context headroom for gpt-oss-20b on an RTX 3080 at Q4\_K\_M__
| Context | KV cache (FP16) | Total at Q4\_K\_M | Verdict   |
| ------- | --------------- | ----------------- | --------- |
| 4k      | 0.1 GB          | 15.6 GB           | Won’t fit |
| 8k      | 0.2 GB          | 15.7 GB           | Won’t fit |
| 16k     | 0.4 GB          | 15.9 GB           | Won’t fit |
| 32k     | 0.8 GB          | 16.3 GB           | Won’t fit |
| 64k     | 1.6 GB          | 17.1 GB           | Won’t fit |
| 128k    | 3.2 GB          | 18.7 GB           | Won’t fit |

From the model’s config. Try other sizes in the [VRAM calculator](https://whatcanirunai.vercel.app/vram-calculator/) or see the [context length guide](https://whatcanirunai.vercel.app/context-length/).

## What to do instead

* Run [Gemma 3 12B](https://whatcanirunai.vercel.app/can-i-run/gemma-3-12b-it/rtx-3080-10gb/) 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](https://whatcanirunai.vercel.app/can-i-run/gpt-oss-20b/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](https://whatcanirunai.vercel.app/best-gpu-for/gpt-oss/) and the [gpt-oss-20b model page](https://whatcanirunai.vercel.app/models/gpt-oss-20b/).

## Other hardware for gpt-oss-20b

* [gpt-oss-20b on an RTX 3060 12GB](https://whatcanirunai.vercel.app/can-i-run/gpt-oss-20b/rtx-3060-12gb/)Won’t fit
* [gpt-oss-20b on an RTX 3070 Ti](https://whatcanirunai.vercel.app/can-i-run/gpt-oss-20b/rtx-3070-ti/)Won’t fit
* [gpt-oss-20b on an RTX 3090](https://whatcanirunai.vercel.app/can-i-run/gpt-oss-20b/rtx-3090/)Fits
* [gpt-oss-20b on an RTX 4060 Ti 16GB](https://whatcanirunai.vercel.app/can-i-run/gpt-oss-20b/rtx-4060-ti-16gb/)Tight
* [gpt-oss-20b on an RTX 4070 Ti Super](https://whatcanirunai.vercel.app/can-i-run/gpt-oss-20b/rtx-4070-ti-super/)Tight
* [gpt-oss-20b on an RTX 4090](https://whatcanirunai.vercel.app/can-i-run/gpt-oss-20b/rtx-4090/)Fits

## Other models on an RTX 3080

* [Qwen3-32B on an RTX 3080](https://whatcanirunai.vercel.app/can-i-run/qwen3-32b/rtx-3080-10gb/)Won’t fit
* [Qwen3-30B-A3B on an RTX 3080](https://whatcanirunai.vercel.app/can-i-run/qwen3-30b-a3b/rtx-3080-10gb/)Won’t fit
* [Qwen3.8-27B on an RTX 3080](https://whatcanirunai.vercel.app/can-i-run/qwen3.8-27b/rtx-3080-10gb/)Won’t fit
* [Gemma 3 27B on an RTX 3080](https://whatcanirunai.vercel.app/can-i-run/gemma-3-27b-it/rtx-3080-10gb/)Won’t fit
* [Gemma 4 31B on an RTX 3080](https://whatcanirunai.vercel.app/can-i-run/gemma-4-31b-it/rtx-3080-10gb/)Won’t fit
* [Mistral Small 24B on an RTX 3080](https://whatcanirunai.vercel.app/can-i-run/mistral-small-3.2-24b-instruct-2506/rtx-3080-10gb/)Won’t fit

## Quick answers

Can I run 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.

How much VRAM does gpt-oss-20b need?

About 15.6 GB at Q4\_K\_M, 26.6 GB at Q8\_0 and 49.1 GB at FP16, estimated for a \~4k context.

How fast is gpt-oss-20b on an RTX 3080?

We do not estimate tokens/sec when the model does not fit. CPU offload is possible but slow.

What context length can I use?

The weights already do not fit, so longer context is not the limiting factor.

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