Can I Run GPT-OSS on NVIDIA H100 80GB (PCIe)?
Written by Jakub Rusinowski · Last updated August 15, 2026
Yes, comfortably — GPT-OSS 120B at Q4_K_M needs 71.9 GB at 8K context (70.5 GB weights + 1.4 GB KV cache/overhead), leaving ~8.1 GB of the NVIDIA H100 80GB (PCIe)'s 80 GB, at ~236 tok/s (est.), with room for up to 64K context.
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NVIDIA H100 80GB (PCIe) Specs
| VRAM | 80 GB |
| Memory Bandwidth | 2000 GB/s |
GPT-OSS 120B on the NVIDIA H100 80GB (PCIe): VRAM by quantization
| Quant | VRAM needed | Fits 80 GB? | Max context | Whole PC |
|---|---|---|---|---|
| F16 | 235 GB | ✗ No | — | — |
| Q8_0 | 125.5 GB | ✗ No | — | — |
| Q6_K | 97.2 GB | ✗ No | — | — |
| Q5_K_M | 84.2 GB | ✗ No | — | — |
| Q4_K_M | 71.9 GB | ✓ Yes | 64K | — |
| Q3_K_M | 51.2 GB | ✓ Yes | 128K | — |
| Q2_K | 39.8 GB | ✓ Yes | 128K | — |
Assumes an 8K-token context with an f16 KV cache. A longer window needs more; a quantized KV cache needs less. “Max context” is the largest window that still fits in 80 GB. Figures are estimates from parameter count, quantization and memory bandwidth — the analyzer lets you tune KV-cache quant and context.
Context costs VRAM too. At Q4_K_M on the NVIDIA H100 80GB (PCIe): 8K 71.9 GB · 32K 73.7 GB · 128K 81 GB ✗. Past 128K it no longer fits 80 GB — a q8_0 KV cache buys roughly half of that back, which the calculator will price for you.
No compatible GPU? GPT-OSS 120B on 96 GB of system RAM, CPU only: runs, but it is tight.
GPT-OSS Sizes That Fit the NVIDIA H100 80GB (PCIe) (at 8K context)
| GPT-OSS 120B | Q4_K_M · 71.9 GB at 8K context · ~236 tok/s (est.) |
| GPT-OSS 20B | MXFP4 · 12.3 GB at 8K context · ~287 tok/s (est.) |
At 2 hrs/day, buying (~$25,000) beats renting at $0.77/hr after about 45.1 years.
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Cloud rates verified 2026-07 — estimates, and marketplace prices vary. Buying price is GPU MSRP only, not a full PC.
FAQ
Is the NVIDIA H100 80GB (PCIe) enough to run GPT-OSS locally?
Yes, comfortably — GPT-OSS 120B at Q4_K_M needs 71.9 GB at 8K context (70.5 GB weights + 1.4 GB KV cache/overhead), leaving ~8.1 GB of the NVIDIA H100 80GB (PCIe)'s 80 GB, at ~236 tok/s (est.), with room for up to 64K context.
What's the best GPT-OSS size for the NVIDIA H100 80GB (PCIe)?
GPT-OSS 120B at Q4_K_M quantization needs 71.9 GB at 8K context (70.5 GB weights + 1.4 GB KV cache/overhead), estimated ~236 tokens/sec, up to 64K context.
Every GPT-OSS size on the NVIDIA H100 80GB (PCIe)
| Size | VRAM at 8K | Verdict | Speed |
|---|---|---|---|
| GPT-OSS 120B | 71.9 GB | Runs | ~236 tok/s |
| GPT-OSS 20B | 12.3 GB | Runs | ~287 tok/s |
GPT-OSS on Other GPUs
Popular Models on the NVIDIA H100 80GB (PCIe)
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