Head to head · October 2026
RTX 3090 vs RX 7900 XTX: which is better for local AI?
24GB against 24GB, 936 against 960 GB/s. What each runs, how fast, and which one to buy.
The verdict
Both have 24GB of memory, so they run the same models. The RTX 3090 generates text about 13% faster thanks to 936 GB/s of memory bandwidth versus 960 GB/s.
- Get the RTX 3090 if speed matters most or you want the widest software support (CUDA).
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Performance
Model by model
Estimated single-user generation speed for popular models, at the best quantization each card can hold with 8K context.
| Model | RTX 3090 | RX 7900 XTX |
|---|---|---|
| Llama 3.1 8B Instruct | ~73 tok/sQ8_0 | ~66 tok/sQ8_0 |
| Qwen3 14B | ~41 tok/sQ8_0 | ~38 tok/sQ8_0 |
| gpt-oss-20b | ~120 tok/sMXFP4 | ~99 tok/sMXFP4 |
| Qwen3 30B-A3B (2507) | ~135 tok/sQ4_K_M | ~110 tok/sQ4_K_M |
| Gemma 3 27B | ~39 tok/sQ4_K_M | ~36 tok/sQ4_K_M |
| Qwen3 32B | ~41 tok/sQ3_K_M | ~37 tok/sQ3_K_M |
| Llama 3.3 70B Instruct | ~1.8 tok/sQ4_K_M Partial offload | ~1.8 tok/sQ4_K_M Partial offload |
| gpt-oss-120b | ~21 tok/sMXFP4 Partial offload | ~20 tok/sMXFP4 Partial offload |
Estimates from our bandwidth model; see methodology. Measured results, where we have them, are on each GPU's page.
Specifications
Spec by spec
| Spec | RTX 3090 | RX 7900 XTX |
|---|---|---|
| Memory | 24GB GDDR6X | 24GB GDDR6 |
| Bandwidth | 936 GB/s | 960 GB/s● |
| Power | 350W● | 355W |
| Price | ~$1,050 used | ~$1,050 used |
| Price per GB | $44 | $44 |
| Architecture | Ampere | RDNA 3 |
| Released | 2020 | 2022 |
| Software | CUDA, Vulkan | ROCm, Vulkan |
Our take
Bottom line on each
The default value pick for 24GB of CUDA memory and the backbone of most multi-GPU builds.
24GB at 960 GB/s with solid ROCm and Vulkan support, though used prices now rival a 3090.
Frequently asked questions
Is the RTX 3090 or RX 7900 XTX better for running LLMs?
Both have 24GB of memory, so they run the same models. The RTX 3090 generates text about 13% faster thanks to 936 GB/s of memory bandwidth versus 960 GB/s.
How much faster is the RTX 3090 than the RX 7900 XTX for AI?
About 13% faster at generating text in our estimates, because token generation is limited by memory bandwidth (936 GB/s vs 960 GB/s). Prompt processing depends more on compute and can differ by more.
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