I have a newly built HTPC
GA-Z68MX-UD2H-B3 (Rev. 1.0)
SSD Intel 510
HD WD 2TB SATA 6G Black
Win 7 64b SP1
latest Driver installed 22.214.171.124.2509
latest BIOS installed f12
Samsung 850 with 4 HDMI ports
I attached the Z68MX to my HDMI port #2 in place of my old ACER AR3610 that I had been using as an HTPC (with NVIDIA ION graphics driver HDMI port).
I noticed that when display switching to different HDMI ports and back to #2 will cause a snowy screen display sometimes -- much like the snow on an old analog TV that was not turned to a proper station. Currently (after improvement listed below) This can still also occure during Post of the Bios of the Z68MX or during Boot of the OS. This even occured last night when loading Adobe Flash and the screen flashed to go to my Administrative OK before installing -- instead it flashed to a snowy screen. When I get a snowy screnn on my Samsung 850 I can get back to my desktop sometimes by rebooting my Z68MX or by switching the display back and forth from #2 to another port and back to #2. A few times I was able to get back to the desktop by powering the Samsung 850 Off/On. Even after all of the work below I still get a snowy screen from time to time when display switching.
So far I've:
changed all my cables -- no impact
changed the ports that the Z68MX was plugged into -- no impact
(NOTE: I testest all of the ports with my AR3610 and had no issues with the display and was unable to force a replication of what I'm experiencing with the Z68MX)
updated all drivers to the latest available from Gigabyte -- some improvement
updated all drivers directly from Intel -- no impact
updated from F2 to F12 BIOS from Gigabyte -- improvement
cleaned hard SSD & HD and re-installed OS and latest drivers -- some improvement
We have tried the latest generic driver for this controller and no similar issues have been seen or detected.
Something that is interesting is the fact the this behavior occurs even when the driver is not present, like booting to the operating system or during post or loading the BIOS, which would indicate a hardware problem.
I suggest you to check the ports on the computer with another model and type of display. If the issue does not occur with another one, this might be a compatibility problem which you should check directly with your motherboard manufacturer.