I use the Belkin F1DN104P - it supports one input and four outputs (DisplayPort 1.1a, 3840x2160@60Hz). I think it's basically the best KVM specs you can find. If you can find anything better then please inform me by PM, haha.

It works fine with my PG278Q Rog Swift. It also works fine with a sordid variety of USB network and video capture hardwares. It turns out that DisplayPort 1.1a and DisplayPort 1.2 are, in the context of this application, fully compatible and interchangeable. At FHD 1920x1080@60Hz and WQHD 2560x1440@60Hz, anyhow.

It doesn't work at 120Hz, sorry. (It just won't, and just can't. But, if manfully forced through ugly hacks, it typically just halts drawing and kicks an onscreen error message back through the OS.)
It does work with G-Sync, up to 60Hz (or up to 60 fps, if you like), but it introduces latencies which apparently load onto the GPU (or force it to slow frame timing) a little. I think a single GPU would lose some fps, but I don't notice significant loss with my 2-SLI GTX980 setup (which almost always assures >60fps at these single-monitor resolutions, anyhow).

My only complaints with the unit - aside from hard technical limits and price tag - are that (contrary to some published info) it enumerates as USB2.0, not USB3.0. Not a biggy, but it's annoying that I cannot use USB3.0 superspeeds on my keyboard's integrated USB3.0 hub. And switching is not quite instantaneous, it takes a tiny fraction of a second to cross over.

I don't really understand the concept of getting a 144Hz display if you then limit it to 60fps. I suppose it helps with dips in fps to eliminate tearing and reduce the stuttering caused by v-sync? Either way this isn't going to work for me if it doesn't support higher than 60Hz. Thank you for the quick reply about your setup. I was curious if a 60Hz rated one would work at all. I may have to look at a different monitor that has two inputs I suppose. =(

I have also been trying to find a genuinely, fully DisplayPort 1.2 compatible KVM switch (i.e., able to support up to DisplayPort 1.2's 2560 x 1600 @ 120Hz limit). Have to say that such a beast does not currently exist as far as I can tell. Tried a Belkin FD102P, but it wouldn't display any refresh rate above 60Hz. At the moment I have a DisplayPort extender cable & physically switch it between my docked DELL Precision M4800 laptop & my Asus Sabertooth 990FX based desktop; using a venerable Aten CS22U K(V)M switch to swop keyboard and mouse between computers. Less than ideal, but it's all that's currently available to the best of my knowledge. If anyone knows better please let me know ASAP!! Rgds., Brian Gregory.

Today, June 22nd, new 0.5m DisplayPort cable arrived. I can confirm that the Lindy 2 Port 4K DisplayPort switch does indeed support 2560 x 1440 @120Hz; & so provides a partial solution to the KVM switch issue - provided that you are prepared to use a cheap conventional KVM switch for toggling keyboard & mouse; in conjunction with the Lindy switch to toggle display inputs. Hope this is a help to other ROG Swift users:cool::cool: