Comparison of Sapphire Radeon RX Vega 56 video card vs Gainward GeForce GTX 1080 Ti Phoenix video card by specifications and benchmarks. Sapphire Radeon RX Vega 56 runs at 1.156 GHz base clock speed and has 8 GB of HBM2 memory, while video card Gainward GeForce GTX 1080 Ti Phoenix runs at 1.480 GHz base clock speed and has 11 GB of GDDR5X memory. The TDP of the first video card is 210 W, and the second is 250 W. Compare the table of benchmark results to find out which graphic card is better.