Comparison of XFX Speedster MERC 319 Radeon RX 6700 XT Black Gaming video card vs XFX Radeon RX Vega 56 video card by specifications and benchmarks. XFX Speedster MERC 319 Radeon RX 6700 XT Black Gaming runs at 2.457 GHz+ 6 % base clock speed and has 12 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 211 W-8 %, and the second is 210 W. Compare the table of benchmark results to find out which graphic card is better.