hi, i have a dual 2.3ghz powermac g5 with 4.5 gigs of ram (early 2005 model). whenever i use the mouse to scroll a page up or down with the center wheel the fan kicks on really loud. it takes a second or two to rev up but then it comes on full force. the fan will stop being really loud as soon as i stop the scrolling. but, if i use the keyboard scroll function or if i use the pointer to scroll the page up or down the fan does not come on (or its not obnoxiously loud). its pretty annoying. is there anything i can do to help/fix this? thanks.