OpenAI · Mixture of Experts · 2025-08

gpt-oss-20b: how much VRAM?

In Q4_K_M with 8k tokens of context, gpt-oss-20b needs about 14 GB of memory. The cheapest option: RTX 4060 Ti 16 GB (€1,350 for the complete machine).

Model sheet

Parameters21 B

Active / token3.6 B

Cache / 1k tok.51 MB

ollama run gpt-oss:20b

Weights on Hugging Face: openai/gpt-oss-20b

Configure the cheapest server →Compare GPUs

VRAM by precision and context

Precision	4k	8k	32k	128k
FP16	45 GB	45 GB	46 GB	51 GB
FP8	23 GB	23 GB	24 GB	29 GB
Q8_0	24 GB	24 GB	25 GB	30 GB
Q6_K	19 GB	19 GB	20 GB	25 GB
Q4_K_M	14 GB	14 GB	15 GB	20 GB
Q3_K_M	11 GB	12 GB	13 GB	18 GB

One user. Each simultaneous user adds their own context cache.

Frequently asked questions

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

With an 8k-token context and one user, gpt-oss-20b needs about 14 GB in Q4, 24 GB in Q8 and 45 GB in FP16.

What is the cheapest hardware to run gpt-oss-20b?

In Q4, the cheapest option in our catalogue to run gpt-oss-20b is RTX 4060 Ti 16 GB, about €1,350 for the complete machine.

How fast does gpt-oss-20b run?

Expect around 69 tokens per second for one user on RTX 4060 Ti 16 GB in Q4 (estimate based on memory bandwidth).

On which hardware?

Hardware	Cards	Speed	Machine
RTX 4060 Ti 16 GB	1 is enough	~69 tok/s	€1,350
Radeon RX 7800 XT 16 GB	1 is enough	~149 tok/s	€1,400
RTX 3060 12 GB	2 cards	~129 tok/s	€1,460
RTX 3090 24 GB (used)	1 is enough	~223 tok/s	€1,650
RTX 4070 Ti SUPER 16 GB	1 is enough	~160 tok/s	€1,750
Radeon RX 7900 XTX 24 GB	1 is enough	~229 tok/s	€1,850
RTX 4080 SUPER 16 GB	1 is enough	~175 tok/s	€1,950
RTX 4070 12 GB	2 cards	~180 tok/s	€2,000
RTX 5080 16 GB	1 is enough	~229 tok/s	€2,100
Mini-PC Ryzen AI Max+ 395 128 GB	1 is enough	~61 tok/s	€2,300
RTX 4090 24 GB	1 is enough	~240 tok/s	€2,900
RTX 5090 32 GB	1 is enough	~427 tok/s	€3,500
NVIDIA DGX Spark 128 GB	1 is enough	~65 tok/s	€4,000
Mac Studio M4 Max 128 GB	1 is enough	~130 tok/s	€4,400
RTX 6000 Ada 48 GB	1 is enough	~229 tok/s	€7,900
RTX PRO 6000 Blackwell 96 GB	1 is enough	~427 tok/s	€9,900
Mac Studio M3 Ultra 512 GB	1 is enough	~195 tok/s	€11,500
L40S 48 GB	1 is enough	~206 tok/s	€13,500
A100 80 GB	1 is enough	~485 tok/s	€17,000
H100 80 GB	1 is enough	~798 tok/s	€34,000
H200 141 GB	1 is enough	~1,143 tok/s	€39,000
B200 192 GB	1 is enough	~1,905 tok/s	€48,000

Estimated complete machine: cards + host PC (€900 for 1–2 consumer cards, €2,800 beyond, a €6,000 server for datacenter cards). Macs and mini-PCs are sold complete.