Question 1

How much VRAM does gpt-oss 20B need?

Accepted Answer

The weights are about 13 GB in its native format (GGUF param count via llamabench.ai (OpenAI model card: 21B total, 3.6B active)). Add memory for context (KV cache) and the runtime. The smallest-memory setup with a measured result here, fully in memory, is RTX 5080 (16 GB) at 204.85 tok/s.

Question 2

What is the fastest measured hardware for gpt-oss 20B?

Accepted Answer

RTX 5090: 313 tok/s generation (llama.cpp, llama-bench tg128 (quant per result)), from https://llamabench.ai/browse/rtx5090.

Question 3

Which GPUs have measured results for gpt-oss 20B?

Accepted Answer

Apple M1 Max, Apple M1 Ultra, Apple M2 Ultra, Apple M3 Ultra, Apple M4 Max, DGX Spark (GB10), RTX 3060 12GB, RTX 3090, RTX 4070 Ti, RTX 4090, RTX 5060 Ti 16GB, RTX 5070 Ti, RTX 5080, RTX 5090, RTX A4000, RTX Pro 6000 (Blackwell, 96 GB), RTX Spark N1X, Radeon AI Pro R9700.

Build	Quant	Engine	tok/s	Cost
RTX 5090: 2026 models (llamabench community)	llama-bench tg128 (quant per result)	llama.cpp	313		source
RTX Pro 6000 96GB workstation card	MXFP4	llama.cpp	286.91		source
Single RTX 5090 32GB	MXFP4	llama.cpp	282.51		source
Intel Core Ultra 265K + RTX 4090		llama.cpp	279.65		source
Single RTX 5080 16GB	MXFP4	llama.cpp	204.85		source
RTX 4090: 2026 models (llamabench community)	llama-bench tg128 (quant per result)	llama.cpp	203		source
Single RTX 5070 Ti 16GB	MXFP4	llama.cpp	189.45		source
Intel Core Ultra 265K + Radeon AI Pro R9700		llama.cpp	163.26		source
Intel Core Ultra 265K + RTX 4070 Ti		llama.cpp	163.14		source
Single RTX 3090 24GB	MXFP4	llama.cpp	161.77		source
Mac Studio M2 Ultra 76-core GPU, 192 GB	MXFP4	llama.cpp	116.08		source
Mac Studio M3 Ultra 512GB (Geerling test)	MXFP4	llama.cpp (Metal, llama-bench)	115.52		source
Mac Studio M3 Ultra 512GB (Geerling test)		llama.cpp	115.29		source
Single RTX 5060 Ti 16GB	MXFP4	llama.cpp	111.51		source
Mac Studio M1 Ultra (64-core GPU) 128GB		llama.cpp	100.43		source
Intel Core Ultra 265K + RTX A4000		llama.cpp	93.55		source
Apple M4 Max 36GB	MXFP4	llama.cpp	92.36		source
Dell Pro Max with GB10 (Nvidia DGX Spark)		llama.cpp	87.97		source
Intel Core Ultra 265K + RTX 3060		llama.cpp	83.96		source
Apple M1 Max 64GB	MXFP4	llama.cpp	75.15		source
HP OmniBook Ultra 16 (RTX Spark N1X, 128GB) laptop: local AI benchmarks	Ollama default, 64K context, Codex CLI coding agent	Ollama	58.0	$6,230 (≈€5,559)	source

Best home rig for gpt-oss 20B

FAQ

How much VRAM does gpt-oss 20B need?

What is the fastest measured hardware for gpt-oss 20B?

Which GPUs have measured results for gpt-oss 20B?