gpt-oss-20b vs Qwen3-30B-A3B: VRAM and speed for running locally
Side by side: how much memory each model needs at Q4, Q8 and FP16, how the KV cache grows with context, the cheapest GPU and Mac that run each, and estimated speed on 11 common machines.
gpt-oss-20b is lighter: about 15.6 GB at Q4 against 22.3 GB for Qwen3-30B-A3B, so it runs on 28 tracked devices vs 16. Qwen3-30B-A3B should be faster on the same hardware, since it reads 3.0B parameters per token against 3.6B. Which one gives better answers depends on your task, so check benchmarks for that; this page covers what it takes to run them.
| gpt-oss-20b | Qwen3-30B-A3B | |
|---|---|---|
| Maker | openai | Qwen |
| License | apache-2.0 | apache-2.0 |
| Type | Mixture of experts | Mixture of experts |
| Total parameters | 20.9B | 30.5B |
| Active per token | 3.6B | 3.0B |
| Memory at Q4_K_M | 15.6 GB | 22.3 GB |
| Memory at Q8_0 | 26.6 GB | 38.3 GB |
| Memory at FP16 | 49.1 GB | 71.2 GB |
| KV cache growth | 49 MB per 1k tokens, FP16 | 98 MB per 1k tokens, FP16 |
| Memory at Q4, 32k context | 16.3 GB 0.8 GB cache | 25.1 GB 3.2 GB cache |
| Cheapest GPU at Q4 | Radeon RX 7900 XT $899 | Intel Arc Pro B70 32GB $949 |
| Cheapest Mac / mini PC at Q4 | Mac mini M6 24GB $1,299 | Mac mini M5 Pro 64GB $3,199 |
| Cheapest GPU at Q8 | Intel Arc Pro B70 32GB $949 | NVIDIA RTX 6000 Ada 48GB $6,799 |
| Tracked devices that run it at Q4 | 28 of 82 | 16 of 82 |
Estimated speed on the same hardware
| Device | gpt-oss-20b | Qwen3-30B-A3B |
|---|---|---|
| GeForce RTX 3060 12GB12 GB usable · 360 GB/s · $329 | doesn’t fit | doesn’t fit |
| GeForce RTX 4060 Ti 16GB16 GB usable · 288 GB/s · $499 | tight fit | doesn’t fit |
| GeForce RTX 508016 GB usable · 960 GB/s · $999 | tight fit | doesn’t fit |
| GeForce RTX 309024 GB usable · 936 GB/s · $1,499 | up to 365 | tight fit |
| Radeon RX 7900 XTX24 GB usable · 960 GB/s · $999 | up to 374 | tight fit |
| GeForce RTX 509032 GB usable · 1792 GB/s · $1,999 | up to 698 | up to 837 |
| Mac mini M6 24GB18 GB usable · 170 GB/s · $1,299 | up to 62 | doesn’t fit |
| Mac mini M6 32GB24 GB usable · 170 GB/s · $1,799 | up to 62 | tight fit |
| Mac mini M5 Pro 64GB48 GB usable · 307 GB/s · $3,199 | up to 113 | up to 135 |
| Framework Desktop (Ryzen AI Max+ 395) 128GB96 GB usable · 256 GB/s · $3,449 | up to 94 | up to 113 |
| MacBook Pro M5 Max 128GB96 GB usable · 614 GB/s · $6,699 | up to 225 | up to 270 |
Hardware that runs only one of them
Run gpt-oss-20b but not Qwen3-30B-A3B: Radeon RX 7900 XT, Radeon RX 7900 XTX, NVIDIA RTX 4000 Ada 20GB, Mac mini M6 24GB, GeForce RTX 3090, GeForce RTX 4090, Mac mini M6 32GB, GeForce RTX 3090 Ti and 1 more.
Quick answers
- Which needs less VRAM, gpt-oss-20b or Qwen3-30B-A3B?
- gpt-oss-20b: about 15.6 GB at Q4_K_M, against 22.3 GB for Qwen3-30B-A3B. At Q8_0 it's 26.6 GB vs 38.3 GB.
- Which is faster locally, gpt-oss-20b or Qwen3-30B-A3B?
- Decode speed is limited by how many bytes are read per token. Qwen3-30B-A3B reads 3.0B parameters per token and gpt-oss-20b reads 3.6B, so Qwen3-30B-A3B should be faster on the same machine. Our estimate on the GeForce RTX 5090 at Q4 is up to 837 tok/s vs up to 698 tok/s. These are estimates, not benchmarks.
- What is the cheapest GPU for gpt-oss-20b and Qwen3-30B-A3B?
- At Q4: Radeon RX 7900 XT ($899) for gpt-oss-20b; Intel Arc Pro B70 32GB ($949) for Qwen3-30B-A3B. Prices are dated list-price snapshots.
- Can a Mac run gpt-oss-20b and Qwen3-30B-A3B?
- The cheapest Mac or mini PC we track for gpt-oss-20b is the Mac mini M6 24GB ($1,299). For Qwen3-30B-A3B it's the Mac mini M5 Pro 64GB ($3,199).
- Which is better, gpt-oss-20b or Qwen3-30B-A3B?
- We don't score answer quality. This comparison covers memory, context cache, hardware and speed. Pick the one that fits your hardware, then test both on your own prompts.
Related comparisons
- Qwen3-30B-A3B vs Gemma 4 26B A4B22.3 vs 19.0 GB
All comparisons · MoE vs dense · Q4 vs Q8 vs FP16 · Context length and VRAM · VRAM calculator