Comparison of XFX Speedster MERC308 Radeon RX 6600 XT BLACK Gaming video card vs PowerColor Hellhound Spectral White Radeon RX 6700 XT video card by specifications and benchmarks. 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, while video card PowerColor Hellhound Spectral White Radeon RX 6700 XT runs at 2.321 GHz base clock speed and has 12 GB of GDDR6 memory. The TDP of the first video card is 160 W, and the second is 230 W. Compare the table of benchmark results to find out which graphic card is better.