Another item to add to your list perhaps?

[Troy Unrau]

Hey guys, perhaps this should go on your list at
http://techbase.kde.org/Schedules/KDE4/4.0_Release_Beta_Goals

KWin Composite has performance issues (big ones) on hardware where
other 3D compositing programs run perfectly smoothly. Perhaps we just
need to optimize for some hardware or something, and it's not a
showstopper (since composite can be disabled), but it will ruin a lot
of first impressions of KWin 4 in it's current state.

Cheers folks

-- 
Troy Unrau
Geophysics Student - University of Manitoba
KDE Gearhead