Comparison of ASRock Radeon RX 6900 XT Phantom Gaming D 16G OC video card vs XFX Radeon RX Vega 56 video card by specifications and benchmarks. ASRock Radeon RX 6900 XT Phantom Gaming D 16G OC runs at 1.925 GHz+ 5 % base clock speed and has 16 GB of GDDR6 memory, while video card XFX Radeon RX Vega 56 runs at 1.156 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 210 W. Compare the table of benchmark results to find out which graphic card is better.