Comparison of ASRock Radeon RX 6600 XT Phantom Gaming D 8GB OC video card vs ASRock Radeon RX 6500 XT Challenger ITX 4GB video card by specifications and benchmarks. ASRock Radeon RX 6600 XT Phantom Gaming D 8GB OC runs at 2.064 GHz+ 5 % base clock speed and has 8 GB of GDDR6 memory, while video card ASRock Radeon RX 6500 XT Challenger ITX 4GB runs at 2.200 GHz base clock speed and has 4 GB of GDDR6 memory. The TDP of the first video card is 160 W, and the second is 107 W. Compare the table of benchmark results to find out which graphic card is better.