Comparison of Sapphire Nitro+ Radeon RX 5700 XT 8G video card vs XFX Speedster MERC 319 Radeon RX 6800 Black Gaming video card by specifications and benchmarks. Sapphire Nitro+ Radeon RX 5700 XT 8G runs at 1.770 GHz+ 10 % base clock speed and has 8 GB of GDDR6 memory, while video card XFX Speedster MERC 319 Radeon RX 6800 Black Gaming runs at 1.850 GHz+ 9 % base clock speed and has 16 GB of GDDR6 memory. The TDP of the first video card is 265 W+ 18 %, and the second is 250 W. Compare the table of benchmark results to find out which graphic card is better.