GPU Fit Matrix
Can the RTX 3090 (used) run gpt-oss-20b?
Yes — fits at FP8
Planning estimate: gpt-oss-20b (20B total) needs about12.5 GB of VRAM at FP4(≈4K context). The RTX 3090 (used) has24 GB.
This is a computed planning estimate (parameter count × bytes/parameter × quantization + context overhead), not a measured benchmark. See how we estimate.
VRAM needed by quantization
| Quantization | Est. VRAM needed | Fits 24GB? |
|---|---|---|
| BF16 | 42.5 GB | ❌ No |
| FP8 | 22.5 GB | ✅ Yes |
| FP4 | 12.5 GB | ✅ Yes |
No measured benchmark yet. We don't publish invented tokens/sec — when we have a first-party measured run for this pairing, it will appear here. For now this page is a VRAM planning estimate. Model the exact case in ourVRAM calculator.
Related
- VRAM calculator — tweak quantization and context for this exact model
- How much VRAM do you need?
- Best GPU for local LLMs
- All GPU × model fit pages