Rent a GPU

Can the Apple M4 Pro (48GB) run gpt-oss 20B?

Apple M4 Pro (48GB) × gpt-oss 20B8K context
YesRuns fully on the GPU
Memory at Q8_023.2 GB of 36 GB
Weights 22.2 GBKV cache 0.4 GBRuntime 0.6 GB
QuantQ8_0Near-lossless
Memory23.2 GBof 36 GB usable
Speed~43tokens per second
  1. FP16
  2. Q8_0
  3. Q6_K
  4. Q5_K_M
  5. Q4_K_M
  6. Q3_K_M
  7. Q2_K

Yes. The Apple M4 Pro (48GB) can run gpt-oss 20B fully in unified memory at Q8_0 (near-lossless), using about 23.2 GB of the 36 GB available, at roughly 43 tokens/second.

Try other context lengths

Run it with Ollama

With Ollama installed, one command downloads and starts gpt-oss 20B:

ollama run gpt-oss:20b

Ollama's default download is Q4_K_M (about 13.7 GB here). You have room for Q8_0, which is near-lossless: pick that GGUF in LM Studio or from Hugging Face.

Run it in the cloud

No Apple M4 Pro (48GB)? Run gpt-oss 20B in the cloud.

Rent a cloud GPU by the hour. No upfront cost, stop any time.

Rent a GPU on RunPodRent a GPU on Vast.ai

Memory needed by quantization

At 8,192 tokens of context. The black line marks the 36 GB the Apple M4 Pro (48GB) can use. macOS lets the GPU use about 36 GB of the 48 GB unified memory by default.

QuantQualityMemoryFits?Speed
FP16Full quality42.8 GBToo big—
Q8_0Near-lossless23.2 GBFits~43 tok/s
Q6_KExcellent18.1 GBFits~55 tok/s
Q5_K_MVery good15.9 GBFits~64 tok/s
Q4_K_MGood, most popular13.7 GBFits~75 tok/s
Q3_K_MNoticeably degraded11.2 GBFits~93 tok/s
Q2_KHeavily degraded8.8 GBFits~121 tok/s

GPUs that run gpt-oss 20B comfortably

Models that run well on the Apple M4 Pro (48GB)

Frequently asked questions

Can Apple M4 Pro (48GB) run gpt-oss 20B?

Yes. The Apple M4 Pro (48GB) can run gpt-oss 20B fully in unified memory at Q8_0 (near-lossless), using about 23.2 GB of the 36 GB available, at roughly 43 tokens/second.

How much VRAM does gpt-oss 20B need?

About 13.7 GB at Q4_K_M with 8,192 tokens of context, and about 42.8 GB at full FP16 precision.

How fast is gpt-oss 20B on the Apple M4 Pro (48GB)?

Roughly 43 tokens per second at Q8_0, estimated from the Apple M4 Pro (48GB)'s 273 GB/s memory bandwidth.