Comparison of XFX Speedster MERC 319 Radeon RX 6900 XT Ultra Gaming video card vs ZOTAC GeForce GTX 1080 Founders Edition video card by specifications and benchmarks. XFX Speedster MERC 319 Radeon RX 6900 XT Ultra Gaming runs at 1.925 GHz+ 5 % base clock speed and has 16 GB of GDDR6 memory, while video card ZOTAC GeForce GTX 1080 Founders Edition runs at 1.607 GHz base clock speed and has 8 GB of GDDR5X memory. The TDP of the first video card is 300 W, and the second is 180 W. Compare the table of benchmark results to find out which graphic card is better.