It's either your Windows, your unstable overclock, poor electrical delivery (PSU / outlet) or faulty cards. I've been running DC work since HD4890 (August 2009) and in 5 years despite overclocked NV/AMD cards doing DC, I haven't had 1 blue screen with any of the driver versions when doing DC work. My system pretty much ran DC 24/7 when not gaming, other than electrical timeouts due to power outages.
The rig is completely stock, no OC. PSU is an Enermax NAXN 350W. I suppose it's possible it's faulty (less than one year old). I'm going to try swapping my practically-new EarthWatts 500W in there.
As far as the monitor not waking from sleep mode, the number of complaints out there seem to suggest the problem is too widespread to be individually-defective cards. (Unless the majority of cards that AMD and their partners churn out are defective.)
I have to ask, what OS were you running? Was it 8 or 8.1? Or 7?
My problems have all been with 8 or 8.1.
My OS install is factory stock, except for installing Waterfox 32.0, CyberPower PowerPanel Personal Edition (UPS software), newest GPU-Z, AMD Cat 14.9 WHQL, ImgBurn, and the newest drivers off of Rosewill's site for my AC1200UBE USB3.0 AC1200 wifi adapter.
Edit: I just swapped PSUs, put in the EarthWatts, booted Win8.1, fired up BOINC, allowed new tasks for Einstein@Home (GPU) and PrimeGrid (CPU), fired up my web browser and internet radio. Guess what? Screen blinks out - AMD driver recovery.
So it's either a crap AMD card, or their crap AMD drivers. Again, nothing is overclocked, this is not a factory OC card that I know of.
Either way, AMD is crap.
Edit: After the display recovery, some of my Waterfox icons in the UI were missing. Had to restart the browser to get them back.
Edit: I left my Lenovo i3-3240 w/7790 1GB GDDR5 doing BOINC, to run out the WUs (Einstein@Home on GPU, PrimeGrid on CPU). Also left my browser open and the internet radio playing.
I went to that PC today, and tried to wake it up. This time, I waited until the monitor booted (it takes some time to power-on for some reason - maybe because it's an HDTV), and then when it said "no signal", I moved the mouse. I got a black screen, BUT HEARD HDMI AUDIO. For a few seconds, it was playing (current) HDMI audio of the internet radio stream. Then it stopped, and I was stuck with a black screen. Had to force power-off and reboot.
Edit: When I rebooted, there were no traces of WUs left, so it must have finished the WUs prior to me trying to wake it up. So it hadn't crashed the PC at all. It just simply doesn't seem to want to wake up the monitor. Monitor is connected via HDMI, HDMI cable that works fine with my other PCs, and an HIS 1GB GDDR5 7790.