I'm using this thread to get various data on what may be causing these iMacs to fail. Theories Tested So Far: Memory "MemVendorID" [FALSE, values same in freezing and non freezing iMacs] drvincom and SG values [FALSE, it was inconsistent] Manufacture Location [FALSE, all same factory] Incorrect CPU fequency in hardware test [Probably Irrelevant] WiFI bug theory (proposed by jebiwan) [TESTING, BUT LOOKING VERY GOOD] Could all iMac owners (including owners of those that work fine) do this test, then fill out this questionaire (the link is below)? TEST (broken iMac owners): If you are using your broken iMac with WiFi on, do this test. If your iMac is broken and you don't use WiFi, just fill out the questionaire. Try to use your iMac with Airport OFF (you can use ethernet). If your iMac is broken, but it works fine with the WiFi off, this this test was "successful" If it still freezes, then this test has failed. TEST (working iMac owners): If you are not using your iMac with WiFi, then you should perform this test. If you are using WiFi and the iMac works, just fill out my questionaire. Turn on the WiFI and connect to a network. See if the iMac works or not. Questionaire: Go here to submit data in a form that I can use more easily: http://www.formspring.com/forms/?595815-QBzGirSBMT Others can view the submitted data here (make sure you select to view all columns): https://www.formspring.com/admin/data.php?595815dGKYXRw1oaK Thanks to all who contribute!