# gpt-oss 20B: RAM and VRAM requirements

> gpt-oss 20B is a 21B gpt-oss model (Mixture-of-Experts, 3.6B active per token). At Q4_K_M it needs about **13.2 GB** to run and fits **16 of 39** tracked devices. Minimum to run: Nvidia GeForce RTX 4060 Ti (16GB).

Last validated: 2026-06-15. Sources: Ollama, HuggingFace GGUF repos, vendor specs.

## Memory by quantization
| Quant | On disk | To run (4k context) |
| --- | --- | --- |
| Q4_K_M | 11.28 GB | ~13.2 GB |

Memory = weights + KV cache + ~0.8 GB runtime overhead, and varies ±15% with context length.

## Will it run on my device?
- **Apple M1 (8GB)** (8 GB): No, not enough memory
- **Generic Android Phone (8GB RAM)** (8 GB): No, not enough memory
- **iPhone 17 Pro** (12 GB): No, not enough memory
- **Nvidia GeForce RTX 4080 (16GB)** (16 GB): Yes, it runs
- **Google Pixel 10 Pro** (16 GB): No, not enough memory
- **Nvidia GeForce RTX 4090 (24GB)** (24 GB): Yes, it runs
- **Apple M4 Pro (48GB)** (48 GB): Yes, it runs — room for Q8_0
- **Apple M3 Ultra (256GB)** (256 GB): Yes, it runs — room for FP16

Full table of all 39 devices: https://localmodel.run/model/gpt-oss-20b

## How to run
Quickest path: `ollama run gpt-oss:20b`. On Mac, LM Studio (ships MLX) is fastest; on Linux, Ollama for chat or vLLM to serve; on Windows, LM Studio or Ollama.

## Details
- Parameters: 21B (MoE, 3.6B active per token)
- Default context: 128k tokens
- License: Apache-2.0 (commercial use: yes)
- Released: 2025-08
- HuggingFace: 4,860,831 downloads/mo, 4706 likes

## FAQ
### How much VRAM or RAM does gpt-oss 20B need?
About 13.2 GB at Q4_K_M (weights 11.28 GB + KV cache + overhead) at a 4k context.
### Can gpt-oss 20B run on a laptop?
gpt-oss 20B is large; you need a high-memory Mac or a 24 GB+ GPU at Q4_K_M.
### Can I use gpt-oss 20B commercially?
Yes, Apache-2.0 permits commercial use.

Sources: https://ollama.com/library/gpt-oss, https://ollama.com/library/gpt-oss/tags, https://huggingface.co/ggml-org/gpt-oss-20b-GGUF, https://huggingface.co/openai/gpt-oss-20b
More: https://localmodel.run/model/gpt-oss-20b