SuB
The Webmaster
Yes. There are two ways of using Sync without using laggy old Vsync in the drivers themselves. Plus there is something called DSR, which basically renders the game and 4k (or even higher if you wish) and then makes it fit onto your screen at that pixel density. So in a nutshell you can run 4k games on a non 4k monitor with most of the detail.
it's the same amount of pixels on your screen though, so it's not really "running at 4k" and you don't really get much more detail, perhaps slightly smoother because you get a kind of super-sampling on jaggies. It's just basically running screen-space multisampling. You run the game at a larger resolution than your screen then it's scaled down and you get more "averaged" pixels than you would running it pure-native.
Protip though, don't bother running Antialiasing on DSR, as you're double dipping and it's a waste of GPU.