Apple's new Core i7-based iMac might be a performance monster, but it looks like the whole family's having some problems getting out of the gate : in addition to the previously-noted performance issues with the Core 2 Duo models, a quick glance across Apple's support forums and on other Mac boards around the web reveals that some machines are showing up DOA and / or with cracked screens. We're a little more familiar with the DOA issue, since the new i7 we just bought doesn't boot at all, but the cracked screen issue seems to be equally common and mostly affecting the bottom left corner, from what we can tell. Now, our review Core 2 Duo 27-inch iMac is perfectly fine, and Chris Ziegler's new Core i7 machine doesn't have any problems either, so these obviously aren't universal issues, but if you're about to stick one of these under the tree for someone it might be wise to do some surreptitious testing first.