Comparison of Sapphire Nitro+ Radeon RX 6800 XT video card vs Gainward GeForce RTX 3090 Phoenix video card by specifications and benchmarks. Sapphire Nitro+ Radeon RX 6800 XT runs at 1.925 GHz+ 5 % base clock speed and has 16 GB of GDDR6 memory, while video card Gainward GeForce RTX 3090 Phoenix runs at 1.395 GHz base clock speed and has 24 GB of GDDR6X memory. The TDP of the first video card is 300 W, and the second is 350 W. Compare the table of benchmark results to find out which graphic card is better.