Comparison of AMD Radeon RX 6800 video card vs PowerColor Liquid Devil Radeon RX 6900 XT Ultimate video card by specifications and benchmarks. AMD Radeon RX 6800 runs at 1.700 GHz base clock speed and has 16 GB of GDDR6 memory, while video card PowerColor Liquid Devil Radeon RX 6900 XT Ultimate runs at 1.825 GHz base clock speed and has 16 GB of GDDR6 memory. The TDP of the first video card is 250 W, and the second is 300 W. Compare the table of benchmark results to find out which graphic card is better.