I know there probably aren't a lot of you out there yet with a similar configuration to mine .... But just wanted to pass along my experiences and see if anyone else has run into them too. I have the new Mac Pro configured with 3 27" LG monitors (IPS panels running at 1920x1200 native resolution). The first one is attached directly to the HDMI output on the nMP, while the second is attached via a Mini-DisplayPort to HDMI dongle. As per Apple's documentation, I purchased the Apple Mini-DisplayPort to dual-link DVI adapter ($99 -- grr!) to make the 3rd. display work properly. (Apparently the nMP can't drive more than 2 displays off of Mini-DP dongles and/or the HDMI port on the back of the machine. If you want to add a 3rd., 4th., etc. and they're not true Apple branded Thunderbolt displays, you need the expensive dual-link DVI adapter for each of them.) So anyway.... that was all fine and well, except after I bought a new triple display stand for my monitors and took all of them off of their factory stands -- my 6 foot HDMI cable barely reached even the display closest to my nMP. So I went out and bought a brand new 12' HDMI cable (a "Craig" branded cable sold at the local CVS pharmacy -- which I know may not be the fanciest brand, but it felt thick and well made enough). Well.... now, it seems whichever monitor I attach that 12' cable to? That monitor has a problem where it powers itself completely off when the nMP puts the displays to sleep. The other 2 screens come right back to life with a click of the mouse and/or tap of the keyboard. I find it hard to believe that the extra 6' of cable length actually makes the signal so weak it starts having these problems, but perhaps so?!