Comparison of XFX Radeon RX 5700 XT Thicc III video card vs PowerColor Red Devil Radeon RX 6900 XT Ultimate video card by specifications and benchmarks. XFX Radeon RX 5700 XT Thicc III runs at 1.670 GHz+ 4 % base clock speed and has 8 GB of GDDR6 memory, while video card PowerColor Red Devil Radeon RX 6900 XT Ultimate runs at 1.825 GHz base clock speed and has 16 GB of GDDR6 memory. The TDP of the first video card is 225 W, and the second is 300 W. Compare the table of benchmark results to find out which graphic card is better.