Comparison of XFX Radeon RX 6900 XT video card vs Gainward GeForce GTX 1660 SUPER Pegasus video card by specifications and benchmarks. XFX Radeon RX 6900 XT runs at 1.825 GHz base clock speed and has 16 GB of GDDR6 memory, while video card Gainward GeForce GTX 1660 SUPER Pegasus runs at 1.530 GHz base clock speed and has 6 GB of GDDR6 memory. The TDP of the first video card is 300 W, and the second is 125 W. Compare the table of benchmark results to find out which graphic card is better.