Hi all. For some time I am experiencing a very disturbing and unpleasant issue: often when I watch a video o listen to music my macbook starts to stutter, in those "stutter-moments" macbook goes non-interactable for small amounts of time. Sometimes it results into a kernel panic, sometimes into a "chronic stutter", that you can see on the second video: stuttering during video: http://www.telly.com/AYWPV6 chronic stuttering: http://www.telly.com/AYWPV6 It looks to be more likely to go into stutter if at least one of the following: - I use my external samsung display. I alway use it at 1980x1080x60Hz. - Macbook gets busy with something else. Seems like the more processor-demanding, the higher is the possibility to go stuttering. - Hi-rez video. But at low-rez it happens too. During investigating I saw that every time the issue takes place, a process "kernel_task" goes processor-binging taking up to 70% of the CPU. Some people advised me to clear the system with Onyx and, after examining one of the kernel panic logs, to remove some of the applications (I removed Oracle Virtual Box and Soundflower). The macbook seems to function smoother after this cleaning, but the issue did not disappear. Then I installed a clear system (also Lion)... the issue is still here. Then I added all of the available updates... the issue is still here. The only difference I saw is that this time, on the new-installed system the "kernel_task" process was not binging. But stuttering still takes place. Then I heard a guess that it could be something about overheating or memory problems. The temperature at which the macbook CPU works is appr. 60-65 C when not very busy and 75-80 C when it is busy. The memory test, which I did on a new-installed system in a single-user mode (command-s when booting), for which I used the memtest, "memtest all 2" command, did not show any problems with memory. Soon after new install of the system I've got a new kernel panic. So, I'm stuck Those are the kernel panic logs: - before cleanup: https://dl.dropbox.com/u/54107411/panic1.rtf - after new Mac OS X install: https://dl.dropbox.com/u/54107411/panic2.rtf P.S. the macbook is core 2 due 2.1, produced somewhere in the middle of 2007, the so-called "black" one (it's black ). There are 2x2 Gb RAM ob board, but the system sees only 3 Gb (some motherboard limitation). There is an SSD, not an HDD inside now.