Posted 03 February 2011 - 09:06 AM
If I am understanding you...what you describe is the routine manner that the system is supposed to work.
When the system is taxed...CPU usage should increase, as evidence of activity beyond that which is beyond the range of not being asked to do certain tasks. The more tasks asked of the system at the same time...the more usage.
Opening/using certain programs should increase CPU usage, with the time for such increase being dependent on what the program is and what it is doing.
Example: If I open and use any of my video-editing programs and proceed to render/edit video...the usage will increase dramatically and reduce only when I have completed the edits/rendering...because those tasks are very intense on the system.
If I am not understanding...please provide more details so that others may be able to contribute their comments/thoughts.