Do they crack that easily? And what makes them crack? I noticed minor imprints on the palm rests were the "feet" so to speak, of the lid go. If it cracks from that I'll march right down to the Apple Store.
Well, it depends. My last logic board had improperly applied thermal paste that had spread all over the breadboard and was leaking out whenever the fan was at max. It resulted in a huge network of cracks on the underside of where my CPU was and the bottom case getting a yellowish hue and feeling really soft to the touch. I expect this was from running a graphics-intensive game on my Windows side (using Tiger's boot camp beta) for 4 hours a day, three days consecutively. Seriously, you should have seen the thing.
The point is it'll crack eventually. I didn't bother for a while because hey, we all look at the bottom of our laptops
so often, but when it started leaking white thermal paste onto my black sofa, well, that's when I went to the Apple Store.
As for the fan, I ran it just last night at 6200rpm (not of my own volition, the system did it for me) for 8 hours while I slept. The CPU was converting all my AVIs to x264 for the Apple TV, with a steady and constant temp of 80 degrees celsius. We're giving every last CPU cycle of the Macs in our house to video conversion. And the fans have been holding up great. I wouldn't worry.
