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Firefox "Smooth Scrolling" Extremely CPU Demanding (On Core 2 Duo...)

Aluminum Sponge

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Hi All,

I am a longtime Firefox on PC user and recently got a new Mac with a pretty spiffy Core 2 Duo processor. I am totally impressed with the speed of the machine, except Firefox scrolling performance when Smooth Scrolling feature is activated. (Preferences > Advanced > "Use smooth scrolling")


Firefox (w/ option enabled) and IE7 both have visually appealing smooth scrolling on even very basic XP PC's with almost no CPU spike. Safari on Tiger comes along with a reasonable 10-20% CPU reported by 'top' utility and minimal Activity Monitor.app CPU Usage palette animation (Both cores level out at about quarter).


Firefox on OS X? When I enable the option in Firefox 2.X I notice it pulls sustained 50-60+% CPU easily simply by scrolling via mouse scroll wheel actively on a long page. Activity Monitor CPU Usage palette easily shows both CPU cores easily reaching 50%+ sustained for the duration of the smooth scrolling action. I've also noticed about 25-30% CPU by scrolling using scroll bar (apparently mouse wheel vs. scroll bar makes a difference). Both cases seems excessive. Firefox at 0.0% when idle.


I know Firefox isn't exactly a 'lite' its toes (Carbon vs Cocoa, XUL, etc), but assumed it shouldn't be taxing a Core 2 Duo CPU in the 55%+ CPU range just for something as basic as smooth scrolling. I love Mac, yet prefer Firefox (compatibility & extensions), and my eyes have just grown very accustom to smooth scrolling all the years from PC Firefox & IE.


1) Is this the standard behavior for Firefox with smooth scrolling activated on a Mac ??

2) Any solution (short of disabling smooth scrolling/ditching Firefox) ??



PS. Same results on several pages tested. No plugins active on page (Quicktime, Flip4Mac, etc). Flash blocked using Flashblock. Advert images blocked (No animated GIFS). Stock Firefox profile. Javascript enabled. Fresh launch.





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