gpt-oss-20b TPS calculator

Open weights OpenAI 20.9B parameters August 2025

Each card below is assessed against this model at the context length and minimum quality you choose. Speed is an estimate for a single request, calculated from the card's memory bandwidth and the size of the model once compressed.

Calculated for this model

241 cards that can run it

818 cards we hold specifications for

Smallest card that fits

Xeon Phi 7120P

16 GB · Q4_K_M · 10.7 tok/s

Fastest card

B200

162 tok/s · 180 GB

Which GPUs can run gpt-oss-20b?

Set the inputs, read the answer

A longer conversation needs more memory, which can push this model off smaller cards.

Hides cards that would only fit the model by compressing it below this point.

241 cards match

Calculating
Needs Quantisation Fit
162 tok/s

97–259 · low confidence

B200 NVIDIA 180 GB 8,000 GB/s Jan 2024 23.1 GB Q8_0 Comfortable
162 tok/s

97–259 · low confidence

B300 NVIDIA 288 GB 8,000 GB/s Sep 2025 23.1 GB Q8_0 Comfortable
129 tok/s

78–207 · low confidence

Radeon Instinct MI350X AMD 288 GB 8,190 GB/s Jan 2025 23.1 GB Q8_0 Comfortable
129 tok/s

78–207 · low confidence

Radeon Instinct MI355X AMD 288 GB 8,190 GB/s Jan 2025 23.1 GB Q8_0 Comfortable
103 tok/s

62–166 · low confidence

Radeon Instinct MI300 AMD 128 GB 6,550 GB/s Jan 2023 23.1 GB Q8_0 Comfortable
99.1 tok/s

59–158 · low confidence

H200 NVL NVIDIA 141 GB 4,890 GB/s Nov 2024 23.1 GB Q8_0 Comfortable
99.1 tok/s

59–158 · low confidence

H200 SXM 141 GB NVIDIA 141 GB 4,890 GB/s Nov 2024 23.1 GB Q8_0 Comfortable
94.8 tok/s

57–152 · low confidence

Radeon Instinct MI325X AMD 256 GB 6,000 GB/s Oct 2024 23.1 GB Q8_0 Comfortable
84.1 tok/s

50–135 · low confidence

Radeon Instinct MI300A AMD 128 GB 5,325 GB/s Dec 2023 23.1 GB Q8_0 Comfortable
84.1 tok/s

50–135 · low confidence

Radeon Instinct MI300X AMD 192 GB 5,325 GB/s Dec 2023 23.1 GB Q8_0 Comfortable
84.1 tok/s

50–135 · low confidence

Radeon Instinct MI308X AMD 192 GB 5,325 GB/s Dec 2023 23.1 GB Q8_0 Comfortable
79.8 tok/s

48–128 · low confidence

H100 NVL 94 GB NVIDIA 94 GB 3,940 GB/s Mar 2023 23.1 GB Q8_0 Comfortable
68.1 tok/s

41–109 · low confidence

H100 PCIe 96 GB NVIDIA 96 GB 3,360 GB/s Mar 2023 23.1 GB Q8_0 Comfortable
68.1 tok/s

41–109 · low confidence

H100 SXM5 80 GB NVIDIA 80 GB 3,360 GB/s Oct 2022 23.1 GB Q8_0 Comfortable
68.1 tok/s

41–109 · low confidence

H100 SXM5 94 GB NVIDIA 94 GB 3,360 GB/s Mar 2023 23.1 GB Q8_0 Comfortable
68.1 tok/s

41–109 · low confidence

H100 SXM5 96 GB NVIDIA 96 GB 3,360 GB/s Mar 2023 23.1 GB Q8_0 Comfortable
68.1 tok/s

41–109 · low confidence

H800 SXM5 NVIDIA 80 GB 3,360 GB/s Mar 2023 23.1 GB Q8_0 Comfortable
52.8 tok/s

32–85 · low confidence

Tesla V100 SXM2 16 GB NVIDIA 16 GB 1,130 GB/s Nov 2019 13.3 GB Q4_K_M Tight
51.8 tok/s

31–83 · low confidence

Radeon Instinct MI250 AMD 128 GB 3,280 GB/s Nov 2021 23.1 GB Q8_0 Comfortable
51.8 tok/s

31–83 · low confidence

Radeon Instinct MI250X AMD 128 GB 3,280 GB/s Nov 2021 23.1 GB Q8_0 Comfortable
44.9 tok/s

27–72 · low confidence

GeForce RTX 5080 NVIDIA 16 GB 960 GB/s Jan 2025 13.3 GB Q4_K_M Tight
43.2 tok/s

26–69 · low confidence

Data Center GPU Max 1550 Intel 128 GB 3,280 GB/s Jan 2023 23.1 GB Q8_0 Comfortable
42.3 tok/s

25–68 · low confidence

Data Center GPU Max Subsystem Intel 128 GB 3,210 GB/s Jan 2023 23.1 GB Q8_0 Comfortable
41.9 tok/s

25–67 · low confidence

Tesla V100 DGXS 16 GB NVIDIA 16 GB 897 GB/s Mar 2018 13.3 GB Q4_K_M Tight
41.9 tok/s

25–67 · low confidence

Tesla V100 PCIe 16 GB NVIDIA 16 GB 897 GB/s Jun 2017 13.3 GB Q4_K_M Tight

Speeds are estimates for a single request — one conversation at a time — calculated from memory bandwidth, model size and quantisation. Real throughput varies with the inference runtime and its version. Figures published by hardware vendors measure many simultaneous requests and are much higher.

On record

Full specification

Everything on record for this model. Most of it describes how it was trained rather than how it runs — useful context for judging how much work went into it, and how it compares with models built at a different scale.

Origin

Who built this model, where, and when it was published.

Organisation
OpenAI
Organisation type
Industry
Country
United States of America
Published
5 August 2025

What it does

The problem areas the model was built for. A model can carry several of each.

Domain
Language
Task
Language modeling/generation, Question answering

Size

How large the model is and how much data it was trained on. Parameters are the figure that decides whether it fits on a given graphics card.

Parameters
20.9B

Total parameters: 20.91B

Training data
tokens

(pretraining FLOPs)/(6*3.6B active parameters)

Training compute

The arithmetic performed to train the model, measured in floating-point operations. It is a measure of what the training run cost, not of how fast the finished model answers you.

Training compute
5.5 × 10²³ FLOP

"The training run for gpt-oss-120b required 2.1 million H100-hours to complete, with gpt-oss-20b needing almost 10x fewer" assuming "almost 10x fewer" means ~9x fewer: 4.94e24/9 = 5.49e23

How it was established
Hardware

The training run

What it physically took to train: which chips, how many, for how long, and what that drew from the wall.

Training hardware
NVIDIA H100 SXM5 80GB

Availability

Whether you can obtain the model and run it on your own hardware, which is what decides if any of the graphics-card figures on this page apply.

Weights
Open — downloadable
Model access
Open weights (unrestricted)

How it is classified

Labels the source dataset applies when tracking notable models, and how confident it is in the entry.

Likely above 10²³ FLOP
Yes
Why it is tracked
Discretionary
Record confidence
Confident

Sources

Where this record came from and when it was last checked.

Reference
gpt-oss-120b & gpt-oss-20b Model Card
Last updated
10 February 2026

The extremes

What the numbers mean

What you need to run it

Minimum card

Xeon Phi 7120P

Memory needed

13.3 GB

Fastest

162 tok/s

With 20.9B parameters, gpt-oss-20b lands in the range a serious desktop card can handle once the weights are compressed. 241 of the cards we track can run it.

The least hardware that works is a Xeon Phi 7120P. Its 16 GB is enough at Q4_K_M compression, giving roughly 10.7 tokens per second.

A B200 is the fastest we calculate for it: about 162 tokens per second, from 8,000 GB/s of memory bandwidth.

Where it came from

gpt-oss-20b was published by OpenAI, in United States of America, in August 2025. The organisation is categorised as industry.

It works in Language, and is recorded as doing language modeling/generation, Question answering.

The weights are published, so it can be downloaded and run on your own hardware indefinitely, offline, with no account attached.

Understanding the speeds

The median result is around 21.0 tokens per second; 198 cards produce text faster than most people read it.

Being dense, it reads all of itself per token, which is why the ordering by speed below follows the ordering by memory bandwidth so closely.

Its internal architecture is not on file, so memory is approximated from the parameter count and marked accordingly. Expect the real figure to differ, more so at long context.

What went into building it

Training it took roughly 5.5 × 10²³ FLOP of computation, on NVIDIA H100 SXM5 80GB — a measure of what producing the model cost, not of how fast it answers.

Its inclusion criterion is discretionary.

Step by step

How to choose a GPU for gpt-oss-20b

The table above has already assessed every card we hold specifications for against this model. Getting to your answer takes six steps.

  1. 01

    Start from the memory column

    Every card here has been checked against gpt-oss-20b — around 13.3 GB at Q4_K_M. Capacity is the gate — a card either holds it or it does not.

  2. 02

    Match the context to your actual use

    Longer conversations cost memory on top of what the weights need. Move the slider to your real working length before trusting any row for gpt-oss-20b.

  3. 03

    Decide how much compression you will accept

    Each card runs the least-compressed copy it can hold — Q4_K_M on the smallest card that fits. Setting a floor drops the cards that only manage gpt-oss-20b by squeezing it further than you would want.

  4. 04

    Compare tokens per second, not specifications

    Ranking by tokens per second for gpt-oss-20b follows memory bandwidth, not core counts, which is why the B200 tops it at 162 tok/s.

  5. 05

    Look at the headroom, not just the fit

    Tight means gpt-oss-20b loads and works, with no room to raise the context later. Comfortable means you can. The difference matters more than a few tokens per second.

  6. 06

    See what else that card runs

    Each card page repeats this sweep for every model we hold. It answers what else the hardware is good for, beyond gpt-oss-20b.

Answers

gpt-oss-20b — common questions

01

How many parameters does gpt-oss-20b have?

gpt-oss-20b has 20.9B parameters. Total parameters: 20.91B. That figure is the total, and it is what decides how much memory the model needs — roughly half a gigabyte per billion at the compression most people use.

02

Who created gpt-oss-20b?

gpt-oss-20b was published by OpenAI, based in United States of America, categorised as industry.

03

When was gpt-oss-20b released?

gpt-oss-20b was published in August 2025.

04

What is gpt-oss-20b used for?

gpt-oss-20b works in Language, and is recorded as handling language modeling/generation, Question answering. These are the areas it was designed around; they describe intent rather than a hard boundary.

05

Where can I download gpt-oss-20b?

The weights for gpt-oss-20b are published, though we do not hold a repository link for it. This site calculates hardware requirements rather than hosting model files.

06

How much compute was used to train gpt-oss-20b?

Around 5.5 × 10²³ FLOP, on NVIDIA H100 SXM5 80GB. That measures what producing the model cost and says nothing about how quickly it answers once trained — inference speed comes from memory bandwidth, not from the training budget.

07

Can I run gpt-oss-20b if it does not fit in my GPU?

It can be split between the card and system memory, but gpt-oss-20b generates painfully slowly that way — the nearest miss we calculate is short by 2.5 GB. Nothing on this page assumes offloading.

08

Would two GPUs run gpt-oss-20b faster?

A second card roughly doubles the memory available but not the generation rate. With 241 cards already able to run gpt-oss-20b alone, the case for pairing is weak.

09

Why does the quantisation differ between cards for gpt-oss-20b?

Each card is shown running the least-compressed copy it can hold, and gpt-oss-20b appears at 4 different compression levels across the cards that fit it. Bigger cards get the more accurate version.

10

How accurate are these gpt-oss-20b speed estimates?

They are calculated from specifications rather than measured, and each carries a range — 97–259 tok/s on the B200, for instance. The same model and card vary by thirty to fifty per cent depending on the inference software and its version.

11

What GPU do I need to run gpt-oss-20b?

The smallest card in our catalogue that holds gpt-oss-20b is the Xeon Phi 7120P, with 16 GB of memory. It runs the model at Q4_K_M using about 13.3 GB, and produces roughly 10.7 tokens per second. 241 cards in total can run it.

12

How fast is gpt-oss-20b on a GPU?

It depends on the card. The quickest we calculate is a B200 at about 162 tokens per second; the slowest that still runs it manages considerably less. Reading speed is around ten tokens per second, and 198 of the cards that can run gpt-oss-20b clear that.

13

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

About 13.3 GB at Q4_K_M compression, which is what the smallest card that runs it uses. Less compression needs more: the figures in the memory column above are recalculated for each card, because each one holds the least-compressed version it can.

14

Can I run gpt-oss-20b on a 16 GB GPU?

Yes. A Tesla V100 SXM2 16 GB with 16 GB runs it at Q4_K_M, using about 13.3 GB and generating roughly 52.8 tokens per second — a tight fit.

15

Can I run gpt-oss-20b on a 24 GB GPU?

Yes. A GeForce RTX 5090 D V2 with 24 GB runs it at Q6_K, using about 18.2 GB and generating roughly 39.4 tokens per second — a tight fit.

16

Is gpt-oss-20b open source?

Its weights are published, so gpt-oss-20b can be downloaded and run on your own hardware. Note that open weights is not the same as open source in the full sense — it says nothing about the training data, the training code, or the commercial terms attached.

Source

Original publication

Record last updated 10 February 2026

The other direction

Looking at it from the other side?

This page starts from the model. If you already own a card and want to know everything it will run, start from the hardware instead.