Version: (using KDE 4.3.4) OS: Linux Installed from: Gentoo Packages With compositing enabled desktop becomes unresponsive while changing the wallpaper.
do you reproduce with kde 4.4.4 or 4.5beta ?
Yes, movies still stop/slow down when wallpaper changes. I've tested it on 4.4.4.
I'm also having this problem on one system but not the other and can perhaps add some vital detail. Both systems have nVidia cards and both use the nv driver. One has desktop effects enabled and works great (no delay in wallpaper transitions, no excessive CPU load). The other system cannot use desktop effects because it's a 3-head system and transitions there typically take 5-10 seconds and cause all other processes to suffer intensely as the load spikes during that time. I'd be most happy to just have an option to disable the fade effect. It's nice where it works well, but it's a pain elsewhere. I assume it must have something to do with hardware acceleration or the lack thereof.
*** This bug has been marked as a duplicate of bug 209152 ***