RTX 4090 vs RX 7900 XTX for local LLMs
VRAM decides which models fit entirely on the GPU; bandwidth decides how fast they generate. Here is how the two cards compare.
Which one for local LLMs?
Both cards have 24 GB of VRAM, so the same models fit on both.
The RTX 4090 has the higher memory bandwidth (1,008 GB/s vs 960 GB/s), so it should generate faster when a model fits on both.
RTX 4090 · Specifications
- VRAM
- 24 GB GDDR6X
- Bandwidth
- 1,008 GB/s
- Board power
- 450 W
- Architecture
- Ada Lovelace
- Largest model fully in VRAM
- Qwen3 32B
Official specData updated 38 days agoSource: NVIDIA specifications
RX 7900 XTX · Specifications
- VRAM
- 24 GB GDDR6
- Bandwidth
- 960 GB/s
- Board power
- 355 W
- Architecture
- RDNA 3
- Largest model fully in VRAM
- Qwen3 32B
Official specData updated 38 days agoSource: AMD specifications
| Model | RTX 4090 · 24 GB | RX 7900 XTX · 24 GB |
|---|---|---|
| Qwen3 32B | Compatible33–45 tok/s | Compatible27–39 tok/s |
| gpt-oss-20b | Excellent212–243 tok/s | Excellent146–201 tok/s |
| Qwen3 30B-A3B | Excellent125–209 tok/s | Compatible81–149 tok/s |
| Llama 3.1 8B Instruct | Excellent112–163 tok/s | Excellent89–137 tok/s |
| Qwen3 14B | Excellent68–95 tok/s | Excellent55–82 tok/s |
| Qwen3 8B | Excellent107–157 tok/s | Excellent84–131 tok/s |
| Llama 3.3 70B Instruct | Not recommended0.9–1.7 tok/s | Not recommended0.9–1.7 tok/s |
| Gemma 3 27B IT | Excellent39–54 tok/s | Excellent32–47 tok/s |
For each model, the highest-precision quantization that runs entirely in fast memory; otherwise the one with the best result. Speeds are ranges; "estimate" unless a benchmark exists for this exact hardware.
EstimateData updated 38 days agoSource: Run LLM Locally engine