This is just a warning to anyone out there thinking about buying a new iMac released last week. DO NOT BUY ONE YET. I received my base model 27" iMac last friday and since day one have had issues with severe slowdown in the system to the point where a 5 year old G5 iMac is faster than this new one. The problem is after using the computer for anywhere from 20 min to and hour depending on how hard you are pushing it the system will become slow and unresponsive. I have tested this from running just iTunes and watching it happen after 40 minutes to running iTunes, Safari and Quicktime all at once and it happening in 20 min. The only thing that helps the problem is to restart the computer and that is only a temporary fix. In a attempt to fix this I have done the following steps below. Taken the computer to the Apple store and gotten a replacement computer with no luck and issue still existing on the new one. It should be noted my first was shipped to me from Apple and the second was picked up in a store several days later. Reinstalled the system with no luck. Did a erase and reinstall with no luck. Plus just to be sure did not use Time Machine to bring my files over in case my old system had something corrupt in it. Did a PRAM reset with no luck Did a repair of permissions and while it did find some to repair did not help. I am convinced at this point the software or hardware is beyond my ability to repair and it is just time to step back and wait for Apple to find the problem and fix it. I have a case opened with Apple Care and am in contact with a employee. Until they resolve this issue I would strongly suggest NO ONE buy a new iMac. UPDATE 10/29/09: Today I wrote a letter to firstname.lastname@example.org explaining situation thus far and 4 hours later was called by a Apple employee claiming to work for Steve Jobs. He took some of my information and directed that I take the second faulty computer to a Apple store asap to have them run tests to determine what the issue is. I took it in tonight and the genius gave me a third computer and said this time he would keep the second unit at the store to run tests on it. He also agreed to contact me to let me know what he finds wrong if anything with the faulty second unit. I am currently typing this on the third new iMac and am NOT transferring any information over until I get the chance to see if this is faulty as well. Currently running Hulu to see if the problems arises. I will continue to update when I determine if this one is better **cross my fingers** UPDATE 2-10/29/09: Third iMac with the original system and nothing else brand new out of the box has same issues after watching a Hulu video for 40 minutes. At this point I give up and will wait for Apple to address this problem. If anyone feels like telling me how I could come across 3 different iMac's all with the same issue please feel free. UPDATE-11/2/09: After reading a couple other threads about this same problem a 27" iMac user mentioned his seemed to respond well to turning off the Airport when the problem arises and then turning it back on. I have tried this about a dozen times and can confirm this does indeed solve the problem. Whatever is causing the iMac system to slow down does seem to respond well to turning off the Airport and then turning it back on again. It should be noted though that like the system restart fix this is only temporary relief and the problem will return after a period of time. On a different note I can also confirm that if you own Bose Companion speakers like myself the new Airport in this iMac causes speaker interference. UPDATE- 11/5/09: I received a phone call back from a Apple executive today who said the problem is with the above mentioned Airport. He said they are working on the problem and should have a update very soon. UPDATE 11/9/09: Apple released OS update 10.6.2 which had now fixed all the above issues. I have been using the computer for over a hour now with no slowdown issues and the interference sounds coming through my Bose speakers is even gone. The machine finally works how it should! Thanks to everyone for their input and suggestions. I would highly recommend purchasing a new iMac now that they have fixed the problem.