So, I've got a new 2010 Mac Pro with the ATI 5870, and right now, I'm thrilled with it. It's hooked up to a Dell U2311H display, and I'm having an odd problem. Hooked up from the DVI port on the video card to the DVI port on the display, everything is fine. Hooked up from the Mini DisplayPort on the video card to the DisplayPort on the display, things seem alright until something happens, like the computer going to sleep, or being turned off. Then, on startup, the screen will remain blank, and the display assets no signal is coming from the computer. As far as I can tell, the only way to fix this is to shut down the computer and switch back to the DVI port. Any idea what's going on?