They have the framerate capped (probably with v-sync enabled on a 144Hz monitor). A card which only achieves 145fps in a game at 1080p isn't getting 108fps at 4K. That's not a possible outcome when you're pushing 4x the pixels, unless you were CPU limited at lower resolutions. However, the game is Prey, which isn't very demanding and doesn't suffer from CPU bottlenecking. From looking at some benchmarks, a 1080 Ti gets over 250fps at 1080p in that game on the highest preset, so they clearly have the framerate capped here to make it seem like the 2.25x option isn't losing you any performance. Incidentally, a 1080 Ti gets ~67fps at 4K in the same game, so they're testing with something much more powerful than that to achieve 108fps rendering at 4K.I don't understand how they are able to render at 2.25x resolution on the card, without any loss of performance? That doesn't sound right to me!