notebook is idle but randomly starts making a lot of noise.

My Macbook all of a sudden started to make a lot of noise while i was on myspace (trying to play a song off a music profile). I quit firefox and the only other open programs were adium & quicksilver. The HD slowly started to slow down. Then while i was away from my computer for a few minutes (wasnt in sleep mode yet) i come back and its doing the same thing again (very loud) like its doing something.. but i dont know what?

what could this be? Could it be myspace? Why?

i have noticed this sortof also. just in the past week since ive started using firefox rather than safari, my CPU seems to be doing alot more work, it spikes up to about 20-40% usage constantly, where as it used to only be at 8-15% cpu usage for all my tasks while i was using safari.

do you use Firefox 2.0? I think I have the same problem too.

yes i do, and it seems once ive started using firefox 2.0, althought its fixed the problem i have had with safari crashing on my a couple times a day with tabbed browsing, it appears to be putting alot of "strain" or use on my processor