Please see my November 23 entry for a discussion of the wake-from-sleep issue with the Mac Pro. This problem ranges in severity to blacking-out the 2nd display, to blacking out both displays and requiring pulling the power plug (hard power cycle). It is an issue with the video card in the 2010 Mac Pro; the good ’ol GT120 card in the 2009 Mac Pro worked properly.
I am sorry to report that the CableMatters.com cable reported by NEC to fix the issue hangs my Mac Pro at startup, and prevents it from booting, same problem as I had with a cable from another vendor.
Since NEC tested that cable, I have no explanation. I’m confirming with NEC that they have tested this configuration.
- Mac Pro 2010 3.33GHz 12-core with 5870 video card
- 30" NEC on DVI
- 27" NEC on DisplayPort
About half the time waking from display sleep is OK, most of the rest of the time the 27" fails to wake up, then about 1/20 the time neither screen wakes up and I have to pull the plug on the Mac Pro.
Also, if I try the hot corner trick to sleep both displays again, coming out of that two quickly invariably kills both screens, and it's pull-the-plug on the Mac Pro.