Comparison of XFX Speedster MERC 319 Radeon RX 6900 XT Black Gaming video card vs KFA2 GeForce GTX 1660 Prodigy video card by specifications and benchmarks. XFX Speedster MERC 319 Radeon RX 6900 XT Black Gaming runs at 1.950 GHz+ 7 % base clock speed and has 16 GB of GDDR6 memory, while video card KFA2 GeForce GTX 1660 Prodigy runs at 1.530 GHz base clock speed and has 6 GB of GDDR5 memory. The TDP of the first video card is 300 W, and the second is 120 W. Compare the table of benchmark results to find out which graphic card is better.