The technique is called Downsampling, achieved via creating a custom resolution in your driver panel.
I have been playing around with this since GTA4 and the infamous ENB-modifications.
Easier to achieve on NV cards than on ATI IIRC (could be totally wrong here, my HD5850 has long gone into my mother´s machine), because you need no monitor timing hacks and such stuff.
For NV cards:
Step 1: Open up NV Control Center
Step 2: Head to Resolution
Step 3: Click "Customize" (this should open up another window, showing all the available resolutions)
Step 4: Click "Create user specific resolution"
Step 5: Check box saying "Activate resolutions that are not available on your display"
Step 6: Create a resolution that is either: 1.5/2/2.5/3 ... times the resolution of your monitor
*You will need to fiddle around at Step 6 a bit, since monitors differ from each other and one might accept higher resolutions than the exact model your brother/mate/... has.
Note, if your techsavvy or patient, you can further tweak your custom resolutions playing around with the timings and all the other options given*
Note :
If your display does not want to accept your new custom resolution it might happen that you are being left with a black screen because the driver has difficulties reverting back to normal.
DONT PANIC here, do a reboot and your standard resolution should be back again.
Sorry that I am not able to help out all the ATI guys, but I dont really wanna travel 18 km on my bicycle just to play around on my mother´s PC which might make my stepfather go apeshit-mental, because of techwar between my brother, me and the aforemetioned only because he keeps installing useless "Administration" (spyware nothing else) tools (read as: effing *****) on a machine that my brother and me had perfectly setup for Ma as a working/gaming rig last Christmas as a proper gift from grateful sons.
Have at it torturing your rigs !
Edit for great justice :
Fiddled around a bit right now and found out my BenQ XL2420T can even stomach
3840x2160 (DS2x) at rounded 44Hz (43.7, but driver rounds up there, dont know why) while DS1,5 (2880x1620) runs at 60Hz.
Ahhh, I can smell the hot circuitry already ^^
Edited by Rad Hanzo, 02 July 2013 - 02:19 AM.