Comparison of PowerColor Red Devil Radeon RX 6900 XT video card vs Biostar Radeon RX Vega 56 8G 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 Biostar Radeon RX Vega 56 8G 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.