RX 7900 XT 20GB vs RX 7900 XTX 24GB for Local LLMs
The RX 7900 XTX 24GB has about 20% more memory bandwidth (960 vs 800 GB/s). Batch-1 decode tracks bandwidth closely, so a model that fits both cards should decode roughly 20% faster on the RX 7900 XTX 24GB. The RX 7900 XTX 24GB fits more of the catalog at Q4/8K — 33 vs 32 of 61 models (24 vs 20 GB VRAM). Largest model that fits the RX 7900 XTX 24GB but not the RX 7900 XT 20GB: gemma-3-27b-it (27.4B). MSRP is $899 for the RX 7900 XT 20GB vs $999 for the RX 7900 XTX 24GB. 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 (46 shared models), the RX 7900 XTX 24GB posts the higher tok/s in 44 rows vs 2. Methodology.