Comparison of Sapphire Pulse Radeon RX 570 8GD5 video card vs XFX Speedster MERC308 Radeon RX 6600 XT BLACK Gaming video card by specifications and benchmarks. Sapphire Pulse Radeon RX 570 8GD5 runs at 1.168 GHz base clock speed and has 8 GB of GDDR5 memory, while video card XFX Speedster MERC308 Radeon RX 6600 XT BLACK Gaming runs at 2.188 GHz+ 11 % base clock speed and has 8 GB of GDDR6 memory. The TDP of the first video card is 150 W, and the second is 160 W. Compare the table of benchmark results to find out which graphic card is better.