From what I’ve read, this seems to affect a large percentage of Gigabyte motherboards since S3 sleep became a ‘thing’.
The issue is as follows: on a significantly overclocked Gigabyte motherboard (high end or low end), when resuming from S3 sleep the screen never wakes up and after about 15-20 seconds, the system repeatedly turns off and on again every few seconds. The only way to break this loop is to completely remove power from the PSU for several seconds.
The issue is connected with PCIe power, as evidenced by the various reported fixes of disabling onboard NIC power saving and reverting from Intel/AMD AHCI drivers to the Microsoft default ones.
The real fix is very simple: Use Balanced power mode in windows and check that PCI Express Link State Power Management is set to ‘Moderate Power Savings’ and not ‘Off’. The fact that the default setting of moderate does not have the issue explains why it is not more widely reported.
Use 120.8Hz custom refresh rate. Both Windows and the monitor’s OSD will show 121Hz. Actual 121.0Hz will cause the error without fail, it must be a tiny bit below. I guess there is something weird going on with the tolerances in the monitor – I’ve noticed things like mains current spikes contribute to the problem.
This may apply more to HDMI 1440×1080 or 1280×720 than to DisplayPort 1080p.
My exact settings for 1440x1080x120Hz over HDMI are as follows:
Just a little tidbit of information regarding Xonar sound cards: The ‘GX’ mode, while I dread to think how deeply it hooks into DirectX (considering it crashes several old games), must be enabled for anything which involves certain clocks to not develop awful judder on the video side of things.
Basically if you use ReClock or play osu!, or anything of that sort (high fps/fast reaction games), enable GX mode. Without GX enabled, I’ve found there to be intermittent severe frame skip, which is only visible to the eye and not to any kind of software FPS or frame loss counter.
If you have a Xonar card and a high refresh rate monitor (it’s not very clear at 60hz), compare GX on and off with http://www.prad.de/en/monitore/testsoftware/pixperan.html.
If I remember correctly, with Aero enabled or Vsync on, the issue is not apparent.