Head-to-head · gpt-oss
gpt-oss 20B vs gpt-oss 120B
gpt-oss 20B needs ~13.2 GB at Q4_K_M; gpt-oss 120B needs ~62.4 GB. That ~49.2 GB gap decides which hardware runs each; they differ on 4 of the 14 devices below.
Which devices run each
A representative spread across the memory range. Tap a verdict for the full breakdown.
Size at each quantization
* derived from bits-per-weight; unstarred sizes are measured GGUF files.
Bottom line
The larger gpt-oss 120B needs ~62.4 GB; gpt-oss 20B runs on lighter hardware at ~13.2 GB with more headroom and faster responses. Check each against your exact device: what runs gpt-oss 20B · what runs gpt-oss 120B.
FAQ
What is the difference in memory between gpt-oss 20B and gpt-oss 120B?
At Q4_K_M, gpt-oss 20B needs about 13.2 GB and gpt-oss 120B needs about 62.4 GB, a difference of ~49.2 GB.
Should I run gpt-oss 20B or gpt-oss 120B?
Run gpt-oss 120B if your hardware has the ~62.4 GB it needs and you want maximum quality; run gpt-oss 20B (~13.2 GB) for lighter hardware, faster responses, and more memory headroom.
Full breakdowns: gpt-oss 20B · gpt-oss 120B · all models × devices.
Sources
Memory figures are estimates at Q4_K_M, validated 2026-08-03. See methodology.