Comparison of XFX Speedster MERC 319 Radeon RX 6800 XT Black Gaming video card vs PowerColor Radeon RX Vega 56 Red Devil video card by specifications and benchmarks. XFX Speedster MERC 319 Radeon RX 6800 XT Black Gaming runs at 1.925 GHz+ 5 % base clock speed and has 16 GB of GDDR6 memory, while video card PowerColor Radeon RX Vega 56 Red Devil runs at 1.308 GHz+ 13 % 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.