Comparison of GIGABYTE Radeon RX 6600 XT Gaming OC 8G video card vs XFX Radeon RX 6900 XT video card by specifications and benchmarks. GIGABYTE Radeon RX 6600 XT Gaming OC 8G runs at 1.968 GHz base clock speed and has 8 GB of GDDR6 memory, while video card XFX Radeon RX 6900 XT runs at 1.825 GHz base clock speed and has 16 GB of GDDR6 memory. The TDP of the first video card is 160 W, and the second is 300 W. Compare the table of benchmark results to find out which graphic card is better.