Gnome -> Xfce with neverball [~Solved]

[Progressor]

I originally installed Isodora Gnome 32 on my almost 5 year old laptop. Recently I decided to try other common DEs (KDE, Xfce, Lxde) next to Gnome and put some effort in mintifying them.

There's one thing that puzzles me:
When running neverball (open source game) under Gnome I had to disable all special graphics settings and setting the resolution to something ridiculously low ('too ugly to bother') to make it run smooth. I used to run Windows XP where I played it smoothly at max graphics settings, and high resolution (1280x800).

I used to assume this came because I'm blessed with a graphic card ATI chose to drop Linux support for (ATI Radeon Mobility X1400). Trying xfce that can't be the reason: It runs neverball smooth at high resolution with only the reflection turned off. (Some exceptions for larger levels.)

(I'd also say the difference is to large to be caused by the minor difference (at least on my laptop) in memory usage between Gnome and Xfce)

So, what causes this?
(And is there something to do about it?)

[Hezy]

I think the most likely reason for the difference is compiz. In Gnome try to turn compiz off, and I think you'll find the performance is as good as in Xfce.

[Progressor]

Completely disabling Compiz got the performance difference down to not noticeable. This kinda amazes me, since I already had really few features of Compiz disabled.
It keeps me wondering...