Maybe I'm just missing some crucial piece of information here.
I built a new system with ASRock motherboard, Intel i5-33750K and my nice MSI R7950 Twin Frozr.
During the install I kept things simple and only ran one monitor (Asus PA248Q, 1920x1200) off the DVI port.
Yesterday I moved the system to my study and attempted to install a second monitor (Asus VW224 1680x1050) as well.
Well, the R7950 has only one DVI port, and since my PA248Q has other connections (HDMI and DisplaPort), I decided to attach the VW224 to the DVI port and the PA248 to the DisplayPort (ASUS included a DisplayPort cable and MSI included a miniDP to DP converter).
THis does not seem to work. My system posts on the VW224 (DVI port), but then as soon as Windows have to start, the monitor goes blank. THe PA248 never seems to get a signal and never comes out of sleep.
If I remove the DisplayPort Connection, my system posts and all is fine.
I see the same behaviour if I attach the DisplayPort cable to the onboard graphics. If I attach the two monitors one to the onboard DVI and one to the DVI on the R7950, they work, but of course this is not good, since CCC only sees one monitor then.
Any advice? I'm heading out to the stores to get some more cables and do more experiments, but the tl;dr is that it seems I have an issue driving my DisplayPort capable monitor from a DisplayPort.