2.6 i7 16 GB Fusion
In the very beginning I had the snow screen once. Nothing since. I started with the Mac mini's converter plugged into a Dell dual VGA cable, then switched to an HDMI cable, and finally, to get 2640x1440, to a mini-DisplayPort to DisplayPort cable. No black screens, not snow except that one time (on VGA).
Black screens are characteristic of digital cables I think, where the data just runs out and there's nothing to show. That could happen when something is slowing the flow down. Not sure what that would be in the mini.