text model · gpt-oss · Windows
Can I run gpt-oss 20B on Nvidia GeForce RTX 4090 (24GB)?
Yes. gpt-oss 20B runs on Nvidia GeForce RTX 4090 (24GB) at Q4_K_M (~13.2 GB of ~23 GB usable).
Runs at Q4_K_M using ~13.2 GB of ~23 GB usable. You have room for Q8_0 for higher quality.
That figure is at a 4k context and moves about ±15% as context length changes. Nvidia GeForce RTX 4090 (24GB) leaves ~9.8 GB of headroom, room to step up to Q8_0 for higher quality.
- Q4_K_M needed
- ~13.2 GB
- Usable on device
- ~23 GB
- Device memory
- 24 GB
- Best quant
- Q4_K_M
Which quant fits
Run it
Pick your tool. All 3 load the same Q4_K_M weights.
ollama run gpt-oss:20b llama-cli -hf ggml-org/gpt-oss-20b-GGUF:Q4_K_M lms get ggml-org/gpt-oss-20b-GGUF - Parameters
- 21B (MoE, 3.6B active)
- Q4_K_M size
- 11.28 GB
- Q8_0 size
- 0.86 GB
- Context
- 128k
- Ollama tag
- gpt-oss:20b
- Memory
- 24 GB vram
- Usable for weights
- ~23 GB
- Power draw
- ~450 W
- Best runtime
- vLLM (Linux) / Ollama (CUDA)
You could also run
Run gpt-oss 20B on other hardware
FAQ
Can Nvidia GeForce RTX 4090 (24GB) run gpt-oss 20B?
Yes. gpt-oss 20B runs on Nvidia GeForce RTX 4090 (24GB) at Q4_K_M (~13.2 GB of ~23 GB usable).
How much memory does gpt-oss 20B need?
Nvidia GeForce RTX 4090 (24GB) has room to spare. At Q4_K_M the weights are ~11.28 GB; with KV cache and runtime overhead, budget ~13.2 GB at a 4k context. It is a Mixture-of-Experts model (21B total / 3.6B active), so all experts must stay in memory; memory tracks total params, not active params.
What is the best tool to run gpt-oss 20B on Windows?
LM Studio for a simple setup; Ollama (CUDA) for the most speed. AMD GPUs run via Vulkan/ROCm at roughly half CUDA throughput. NVIDIA is the smooth path on Windows.
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A live badge for your model card or README, updated as the data is. [](https://localmodel.run/can-i-run/gpt-oss-20b/nvidia-rtx-4090-24gb) Sources
Weights are measured from GGUF files; KV cache and overhead are computed, so totals can vary ~15% with context and runtime. Any tok/s is a bandwidth estimate. See methodology.