I have my new 15" 2011 model for little over a week and keep noticing random lock-ups for no apparent reason. The model is the high end 15" with the standard 2,2GHz i7, 4GB RAM, 750GB Harddisk (5200RPM) and the only custom option was the glossy high resolution screen. Right after I got it I booted OSX and tested whether the machine worked correctly. Afterwards I reinstalled OSX because I wanted a 3 partition setup for OSX, Data and Windows 7. Something that cannot be done with bootcamp. I reinstalled to prevent any problems that might pop up. When setting up my machine I noticed some lockups but did not think to much of it. I was transferring about 200GB of data and installing multiple programs as well as importing my iTunes library and syncing both my iPad and iPhone. When doing all this I can understand that starting firefox and watching some youtube videos can even topple the performance of the 15" a little. However after installation I only run a limited amount of applications at a time, and most are background applications like growl, sparrow, dropbox and delibar. When switching between path finder, firefox and reeder for example the beachball of dead keeps popping up. Sometimes I type and there is a 2 second delay before everything just appears on my screen fast. After having this for a while I reckoned the installation might be botched. I have had it before on my 2008 Mabook (C2D, 4GB Ram, Intel Integrated Graphics). After wiping the disk and reinstalling the problem did occur but not as much as before. But still is apparent. I am still bothered with this delay because my 2008 with an aged C2D and Intel GMA did not any delay whatsoever. I reckoned it could be my RAM but memtest (run in single user mode) did not return anything. Neither did the Apple Hardware Check on both the short and long tests. I have run some TechTool Pro checks but found nothing either. Still have to run the full tests though. I checked the harddisk but it does not seem to have any I/O errors and otherwise it behaves correctly. I know 5200RPM is on the slow side compared with the 7200RPM and SSD's. But I somehow manage to play a total of four 720p files of 1GB each fullscreen without any problem whatsoever, but simply switching from firefox to path finder locks up my computer. I don't think this problem is harddisk speed related. I have a 7200RPM disk that always worked fine in the 2008 macbook that can be installed, but I don't feel it's the problem and reinstalling everything will take me a few hours again. 4GB of RAM was always enough to run the exact same programs on the 2008 macbook, so it should be more than enough on the 2011 MBP. I did notice that my HD6750M is always running because of Sparrow, Delibar and CloudApp. These applications launch at startup and seem to use API's that Apple considers to be needing Discrete graphics. As a result my HD3000 will never be used, unless I manually change it withgfxCardStatus. But i would expect my MBP to perform better not worse with the HD6750M turned on. My fans run at 2000RPM under normal circumstances and the CPU is around 50~60 degrees Celsius. Using SMCcontrol I upped the RPM to 2500 and the CPU runs at about 40~50 now, but the problem still exists. Any other people that have this problem, or any tips on what to try next.