Scrolling in a window vs. moving the window


I noticed that clicking on a blue slider bar inside a window and scrolling is painfully slow and staggered on a G3 400MHz, 384MB RAM, ATi Rage 128 video card, however, clicking on the window itself and moving the window very quickly is not a problem with no visible lagging / staggering. Moving the window even with animation in it (QuickTime movie) is very smooth with no lagging / staggering. What gives? Why does Mac OS X have such a problem scrolling and no problems moving windows? I can't believe Apple is purposely crippling the OS so we all will go out and purchase brand new G4's.
Don't worry about the conspiracy. I've got a G4 Titanium, and scrolling is still pretty slow. I've no idea why. Hopefully they're working on it.

I have posted this elsewhere but it bears repeating.

Cocoa and Carbon to not take advantage of OS X's video acceleration as much as they could WRT scrolling.

Basically 2D acceleration in OS X is limited to moving 2D surfaces in and out of video memory by the kernel, however only whole windows are being paged, not sub-views. Specifically NSClipViews ought to be using video memory contexts to display graphics thus when scrolling the surface would be moved and the only portion updated would be the previously invisible portion.

QuickDraw is also not taking advantage of this. QuickDraw has functions especially for scrolling so in MacOS the only portion moved to the frame buffer is the previously not visible portion. In OS X the entire port is being updated.

It's stupid!