Ryzen AI Max 390 64GB vs RX 7900 XT 20GB for Local LLMs
The RX 7900 XT 20GB has about 272% more memory bandwidth (800 vs 215 GB/s). Batch-1 decode tracks bandwidth closely, so a model that fits both cards should decode roughly 272% faster on the RX 7900 XT 20GB. The Ryzen AI Max 390 64GB fits more of the catalog at Q4/8K — 41 vs 30 of 69 models (48 vs 20 GB VRAM). Largest model that fits the Ryzen AI Max 390 64GB but not the RX 7900 XT 20GB: Qwen3-Next-80B-A3B-Instruct (81.3B). MSRP is $1,300 for the Ryzen AI Max 390 64GB vs $899 for the RX 7900 XT 20GB. MSRP is a launch list price, not live retail — Amazon prices move; click through for the current price. In the Q4/8K head-to-head below (50 shared models), the RX 7900 XT 20GB posts the higher tok/s in 41 rows vs 9. Methodology.