Quite often then my monitor goes back to power mode after being in power saving mode (which is initiated after defined period of inactivity), there is just black screen, however it seems like everithing is working besides that malfunction. Note: only monitor goes into sleep mode, CPU is working all the time.
Sometimes by tapping different keyboard keys I'm able to make it show something, but usually I just have to press power button, so it gracefully performs power off.
I've used this mode for a long time with Windows 7 Pro x64, but started expiriencing this after upgrade to Windows 8 Pro x64.
My best guess that can probably be caused by buggy AMD video driver, but I'm not sure is there anything I can do about this if not only waiting for a new driver?
I'm using Catalyst Version 13.1 with Radeon HD 7770 graphics card, Dell U2412M monitor connected with DVI cable.