I have just set Ubuntu 12.04 64bit with Cinnamon desktop and 3.5.0-030500 kernel on my new laptop with IvyBridge i7.

I decided to test its performance by running a single threaded CPU-hungry program that I often use for camera calibration. Unfortunately, it ended up running much slower than I have ever expected. After some investigation it turned out that the program priority is automatically changed from normal to low which makes the program even slower.

I have also noticed that all user programs such as Skype and Firefox are set to low priority. I tried manually resetting the priority to normal or even very high using the "renice" command, which works temporary until the kernel scheduler (I guess) resets the priority to low. Is this a normal behaviour and how can I overcome the problem with slowing down the execution?

P.S. I also tried with the 3.2 kernel, but the problem is still present.