Comparison of XFX Radeon RX 580 Double Dissipation 8GB video card vs MSI Radeon RX 6600 MECH 2X 8G video card by specifications and benchmarks. XFX Radeon RX 580 Double Dissipation 8GB runs at 1.257 GHz base clock speed and has 8 GB of GDDR5 memory, while video card MSI Radeon RX 6600 MECH 2X 8G runs at 1.626 GHz base clock speed and has 8 GB of GDDR6 memory. The TDP of the first video card is 185 W, and the second is 132 W. Compare the table of benchmark results to find out which graphic card is better.