[gentoo-hardened] overlapped windows in x

Hi all!

I'm having a problem with overlapping windows: 
if I change to a window in the background (for example to the browser), the content 
of the hidden part is drawn back slowly: i see a grey square for a moment
Also, moving a window on the top of the browser is very slow.

So, could this happen because of the hardened profile. 
I was using desktop profile for 1,5 years, but I honestly don't remember if I 
had problems there.
I tried ubuntu livecd for comparison, and there was no problem with
windowing.

I use the hardened profile with hardened kernel.
I don't know where to paste more information. Sould I use the mailing list, or
a pastebin-like web page?

I'm using xf86-video-ati with radeon 7500.

Thank you for reading...
bendeguz