I found that the tip for improving graphic performance of my old ATI Rage Mobility 7500 (IBM T41) outlined in this thread - http://www.pclinuxos.com/forum/index.php/topic,67549.0.html
is still necessary for 2010 KDE4.4
On installing 2010 my gtk apps, firefox, thunderbird etc were taking ages to start and scrolling web pages was very sloooow with block redrawing/tearing visible.
I tried changing from the ATI driver to the xorg driver, no joy.
Then I remembered
Basically you should remove the gtk-oxygen-molecule theme by installing the gtk-qt-engine and qt-curve.
See AndrzejL's post onwards at bottom of first page.