Comparison of MSI Radeon RX 580 Armor MK2 8G OC video card vs XFX Speedster MERC308 Radeon RX 6600 XT BLACK Gaming video card by specifications and benchmarks. MSI Radeon RX 580 Armor MK2 8G OC runs at 1.257 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 185 W, and the second is 160 W. Compare the table of benchmark results to find out which graphic card is better.