Comparison of PowerColor Red Devil Radeon RX 6900 XT video card vs XFX Radeon RX Vega 64 Black Fan video card by specifications and benchmarks. PowerColor Red Devil Radeon RX 6900 XT runs at 1.825 GHz base clock speed and has 16 GB of GDDR6 memory, while video card XFX Radeon RX Vega 64 Black Fan runs at 1.247 GHz base clock speed and has 8 GB of HBM2 memory. The TDP of the first video card is 300 W, and the second is 295 W. Compare the table of benchmark results to find out which graphic card is better.