Radeon RX 7800 XT vs Radeon RX 7900 XT for Local AI
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Which GPU is better for local AI workloads?
The 7900 XT's 20GB is an odd-but-useful capacity: it fits 32B LLMs at tight Q4 and gives image batching headroom. The 7800 XT is the value 16GB pick. Both are gfx1100-class with solid ROCm support.
Spec comparison: what actually differs
The table below is computed live from our hardware database. Positive deltas favor the Radeon RX 7800 XT.
| Specification | Radeon RX 7800 XT | Radeon RX 7900 XT | Difference |
|---|---|---|---|
| VRAM | 16 | 20 | -20% |
| Memory bandwidth | 624 | 800 | -22% |
| Memory type | GDDR6 | GDDR6 | — |
| Memory bus | 256 | 320 | — |
| TDP | 263 | 315 | -17% |
| Stream processors | 3840 | 10752 | -64% |
| Architecture | RDNA 3 | RDNA 3 | — |
| Launch MSRP | $499 | $649 | -23% |
| Street price | $499 | $649 | -23% |
What about price?
Which one should you buy for LLMs and image generation?
Radeon RX 7800 XT
Buy the 7800 XT for straightforward 16GB value.
Full specs & benchmarks →Radeon RX 7900 XT
Buy the 7900 XT used/discounted for 20GB-class capacity.
Full specs & benchmarks →Is it faster for LLM inference?
20GB holds 32B at IQ4/Q4-tight; 16GB tops at 14B Q8. Decode faster on 800 vs 624 GB/s.
How does it handle image generation?
Both run Flux; 7900 XT batches harder.
Which AI models fit on each card?
Computed from our model VRAM database at Q4 quantization: Radeon RX 7800 XT has 16 GB, Radeon RX 7900 XT has 20 GB.
Fit only on the Radeon RX 7900 XT (20 GB)
Fit on both cards
Frequently asked questions
7800 XT vs 7900 XT for LLMs?
7900 XT: 20GB fits 32B models at tight Q4 quants; 7800 XT's 16GB stops at 14B Q8. Bandwidth 800 vs 624 GB/s also favors the XT.