Hi, I recently got the 2.4 20" iMac. Since a lot of people recommended Crucial for the memory upgrade. I went ahead and ordered 4GB from Crucial. I had my iMac for about 1 week before I put in the new memory. I never noticed it freezes on me at all before I put in the memory. After I put in the memory, it intermittently freezes and there's nothing I can do except hold down the I/O button to turn it off. It would freeze for no reason, but I noticed it freezes often when I used Handbrake to rip a DVD or even when I'm in Numbers doing just usual stuff. Finally today I put back the 1GB that the iMac came with, and so far, Handbrake is going OK. Could the new Crucial memory be bad? Should I call them up and ask for a replacement or return? Has anyone had this problem? Thanks for your help.