The RTX 3090 24GB has about 50% more memory bandwidth (936 vs 624 GB/s). Batch-1 decode tracks bandwidth closely, so a model that fits both cards should decode roughly 50% faster on the RTX 3090 24GB. The RTX 3090 24GB fits more of the catalog at Q4/8K — 33 vs 25 of 61 models (24 vs 16 GB VRAM). Largest model that fits the RTX 3090 24GB but not the RX 7800 XT 16GB: GLM-4.7-Flash (31.2B). MSRP is $1,499 for the RTX 3090 24GB vs $499 for the RX 7800 XT 16GB. 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 (44 shared models), the RTX 3090 24GB posts the higher tok/s in 36 rows vs 8. Methodology.