Macbook cpu problem extreme frequent slowdown and subs performance problems

Question

Hello
Since summer 2007 we have been experiencing speed problems with one of our Macs a Macbook bought in 2006. Initially we thought it was just because we were asking too much of the computer. But unfortunately this is not the case. What happens is that while working normally (normal performance) with one or more applications, the computer starts to slow down to a near halt. You notice this because instead of for example opening a new window right away it slowly unrolls the window until it is open. At the same time the fan starts to accelerate and often the little color wheel appears instead of the mouse arrow. The computer is warm but not hot. Usually after a while the speed of the computer comes back to normal and the fan will stop turning at high speed. When checking cpu usage during such an "episode" most of the time cpu usage by Safari or Firefox Activity monitor indicates cpu usage by Safari and Firefox 100-110 % which strikes me as not being right . Quitting these programs seems (seems !) to return the computer to normal faster. The Apple store has replaced the memory, no effect, I did a total clean install of OS, updated it to the latest version of Tiger no effect. What can be the problem ? Is it the logic board as a whole or the graphics portion ? Or is something blocking the vent and it does not cool sufficiently? We are at a loss what to do.
Any advise would be appreciated. Right now all I can think of is to bring the computer in to an Apple Care Center probably resulting in a high bill even though in retrospect this problem started before the expiry of the Apple warranty.
Many thanks for any help.
H van Es

Answer 1

nlesh wrote:
Hello thanks,
We use websites like Wall Street Journal online, viamichelin.fr, yahoo, NCBI. I may have given the wrong impression that it only happens with internet use, it also happens with iMovie or Nikon capture NX but I guess we just notice it more with internet use because this computer is mostly used for that plus e-mail.
H van Es
I took a look at those sites. I noticed several ad/content displays on online.wsj.com which probably used Flash or Java animation/video. Yahoo! typically has tons of animation features (especially stuff like falling snow on holidays), and viamichelin.fr has a bunch of animated ads. NBCI looks to be the nastiest of the bunch.
If your fan is turning on from having multiple websites like those on, I'm not surprised.