Hi,
 
at first I wanna say that I'm from germany and therefore my english is not that good, so please be gentle
 
I've found a short article on PCGH which explains the technique behind downsampling.
 
http://www.pcgameshardwar...ith-Downsampling/News/
 
The link inside the article refers to the 3DCenter Forum(in german). If you like to try downsampling you'll have to follow the steps which are shown in the videos.
 
Tools needed
 
1. softMCCS
2. Phoenix
3. Monitor Asset Manager
http://www.megaupload.com/?d=S7XHCZ6J
 
 
1. DX9 (reboot required after display driver installtion) http://www.oc-burner.de/f...chritte_%28DX9%29.html
 
2. DX10 / 11 (reboot required after changing the reg stuff) http://www.oc-burner.de/f...n_%28DX10-DX11%29.html
 
I'd be glad if someone could help me after doing these steps with my problem. Downsampling works at my rig in DX 9 @3360x2100@50hz without any issues. (It seems that every monitor can provide 2880x1800(for 1920x1200 native) and 2880x1620@60hz) But as soon as I edit the nv_modes reg-keys(like in the video), the resolution which I've added to the nv_modes string will be some kind of "blocked" and can not be chosen whether in DX 9 nor in DX10/11. Removing the resolution from the custom resolution and adding them again to it is not possible.
 
I've already tried several driver versions under Vista and Windows 7, but the problem remains. Even the updated bios for the GTX580 won't help. For me it seems that this seems to be an GT5XX issue, because any GT4XX user could force downsampling under DX10/11. At this moment there are 3 other persons who have the same problem with their GTX580.
 
Maybe some EVGA Staff or Mod knows more about any driver restrictions or bugs which may cause this.
 
Thanks for your help
 
My rig:
i7 920 D0
12GB DDR3 Ram
Gigabyte EX58 UD5
EVGA GTX 580
Win 7 Ultimate 64bit
Monitor Samsung T240 (using DVI connection between GTX580 and monitor)