GPT-OSS 120B needs ~96.4 GB VRAM. NVIDIA GB200 192GB has 192.0 GB. With Q4_K_M quantization, expect ~102 tok/s.
Operating mode
Interactive favors responsiveness, while light API and scale-out lean harder on serving readiness. The fit stays the same, but the recommendation lens changes.
Current mode
Balanced
Balanced for general local use. Keeps the ranking neutral across personal and serving workflows.
Select quantization to explore
Fit status
Runs well
Decode
102.4 tok/s
TTFT
1891 ms
Safe context
131K
Memory
96.4 GB / 192.0 GB
This setup is broadly balanced for this model.
No major red flags
This recommendation has enough memory headroom and acceptable estimated speed for the selected workload.
| Workload | Grade | Fit | Decode | TTFT | Context |
|---|---|---|---|---|---|
| Chat | S | Runs well | 102.4 tok/s | 1031 ms | 131K |
| Coding | S | Runs well | 102.4 tok/s | 1891 ms | 131K |
| Agentic Coding | S | Runs well | 102.4 tok/s | 2750 ms | 131K |
| Reasoning | S | Runs well | 102.4 tok/s | 2234 ms | 131K |
| RAG | S | Runs well | 102.4 tok/s | 3438 ms | 131K |
Inference speed
Estimated decode speed (tokens/sec) for GPT-OSS 120B at Q4_K_M across popular GPUs and Apple Silicon, including multi-GPU rigs, using the fastest local runtime per device. Fastest is MacBook Pro M4 Max 128GB at ~9 tok/s. Speed is memory-bandwidth bound, so cards that fit the whole model in VRAM run far faster than ones that offload to system RAM.
| GPU / Mac | Memory | Quant | Speed (tok/s) | Fits? |
|---|---|---|---|---|
MacBook Pro M4 Max 128GB | 128 GB | Q4_K_M | 9.2 | Offloads |
Mac Studio M3 Ultra 256GB | 256 GB | Q4_K_M | 8.5 | Fits |
Mac Studio M2 Ultra 128GB | 128 GB | Q4_K_M | 7.1 | Offloads |
Mac Studio M1 Ultra 128GB | 128 GB | Q4_K_M | 6.7 | Offloads |
2× RX 7900 XTX 24GB | 48 GB | Q4_K_M | 4.4 | Too big |
MacBook Pro M4 Max 64GB | 64 GB | Q4_K_M | 4.3 | Too big |
| 48 GB | Q4_K_M | 3.1 | Too big | |
MacBook Pro M4 Pro 48GB | 48 GB | Q4_K_M | 2.6 | Too big |
| 48 GB | Q4_K_M | 2.6 | Too big | |
| 48 GB | Q4_K_M | 2.3 | Too big | |
| 32 GB | Q4_K_M | 2.0 | Too big | |
| 24 GB | Q4_K_M | 2.0 | Too big | |
| 16 GB | Q4_K_M | 2.0 | Too big | |
| 24 GB | Q4_K_M | 2.0 | Too big | |
| 12 GB | Q4_K_M | 2.0 | Too big | |
| 12 GB | Q4_K_M | 2.0 | Too big | |
| 8 GB | Q4_K_M | 2.0 | Too big | |
RX 7900 XTX 24GB | 24 GB | Q4_K_M | 2.0 | Too big |
MacBook Pro M3 Max 64GB | 64 GB | Q4_K_M | 2.0 | Too big |
MacBook Pro M1 Max 64GB | 64 GB | Q4_K_M | 2.0 | Too big |
Estimates for single-stream decoding at Q4_K_M; real tokens/sec varies with prompt length, context, batch size, and runtime build. Prompt processing (prefill) is faster than the decode figures shown here.
How GPT-OSS 120B (117B params) fits at each quantization level on NVIDIA GB200 192GB (192.0 GB usable).
| Quant | Bits | VRAM | Quality | Fit |
|---|---|---|---|---|
Q2_K | 2 | 45.6 GB | Low | A81 |
Q3_K_S | 3 | 57.3 GB | Low | A83 |
NVFP4 | 4 | 65.5 GB | Medium | A84 |
Q4_K_M | 4 | 71.4 GB | Medium | A84 |
Q5_K_M | 5 | 84.2 GB | High | S86 |
Q6_K | 6 | 95.9 GB | High | S87 |
Q8_0Best for your GPU | 8 | 125.2 GB | Very High | S88 |
F16 | 16 | 239.8 GB | Maximum | F0 |
Copy-paste commands to run GPT-OSS 120B on your machine.
Run
ollama run gpt-oss:120bYour hardware
| Model | Params | Grade | Decode | Capabilities |
|---|---|---|---|---|
| 123B | S | 97.4 tok/s | ||
| 122B | S | 270.2 tok/s | ||
| 284B | S | 144.8 tok/s | ||
| 119B | S | 292.9 tok/s |
Yes, NVIDIA GB200 192GB can run GPT-OSS 120B with a S grade (Runs well). Expected decode speed: 102.4 tok/s.
GPT-OSS 120B (117B parameters) requires approximately 96.4 GB of memory with Q4_K_M quantization.
The recommended quantization for GPT-OSS 120B is Q4_K_M, which balances quality and memory efficiency.
On NVIDIA GB200 192GB, GPT-OSS 120B achieves approximately 102.4 tokens per second decode speed with a time-to-first-token of 1891ms using Q4_K_M quantization.
For coding workloads, GPT-OSS 120B on NVIDIA GB200 192GB receives a S grade with 102.4 tok/s and 131K context.
On NVIDIA GB200 192GB, GPT-OSS 120B can safely use up to 131K tokens of context. The model's official context limit is 131K, but available memory constrains the safe maximum.
Paste this snippet into any page to show a live fit card.
<iframe src="https://willitrunai.com/embed/gpt-oss-120b-on-gb200-192gb" width="400" height="180" frameborder="0" style="border:none;border-radius:12px;overflow:hidden;" title="Will It Run AI — fit result"></iframe>
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