Hello, everybody.
I'm getting a bit annoying trails when moving windows in X.
It doesn't matter if I use KDE, Fluxbox, XFCE, etc - all the same effect.

This screenshot shows what the problem is exactly.
This happens when I move a window over another.
In this case the Ktorrent window over Opera.

Also there's another "effect", specific to KDE, that I've noticed: here.
It happens every time I choose Open new tab.
Also, when moving windows fast one over the other,
all the icons of the underlying window disappear,
the text also, only the outlines of the window remain.

The interesting thing is that when I enable the Composite Extension in X,
these problems disappear...
However, I don't want to use Composite for various reasons I won't list here.

I have tried using all kinds of combinations of X11 versions,
xorg.conf and window managers. And it happens on a clean install also;
and using a liveCD, too.

When i googled a few days ago I read somewhere that it could
be a bug in the videocard chipset/driver or something...
I read the man page of the radeon driver searching for
options to put in xorg.conf, which might help, but nothing did.

So, if anybody has any ideas why this happens, I'll be glad
to hear from you.
I know it may seem like a detail but I just wanna know why it happens


PS:
My configuration:
ATI Radeon 9200, 128MB
"radeon" open-source driver
Xorg 6.9.0
Slackware 11.0

I suggest you use ATI Driver. IMO it is still a lot faster on direct rendering ( I'm not even sure if direct rendering is supported on open source driver )

To be sure this issue has something to do with 3d acceleration, and not some cpu consuming process, use top to monitor process activities.

I don't think that this is related to direct rendering.
BTW, I checked the 'Similar Threads', two (1st, 2nd) of them described the same problem like mine. But none was solved, and both of the users are with ATI cards... And one of them uses the proprietary driver with DRI and OpenGL.
So, I guess I'll just have to accept that this is a bug in the radeon chipset or something...
The interesting thing for me is, how come enabling the composite extension eliminates these problems

OK,

I think I found a workaround. As I previously posted, I don't want to use shadows and translucency, provided in KDE, because it slows down my system, and even after some time running, my CPU hops to persistant 100% CPU usage, until i reinitiate the kcompmgr process.

So what I did, I made xcompmgr to autostart with KDE, but I disabled the translucency option in KDE Control Center (and by doing so preventing kcompmgr from starting, because I think it's more resource-hungry than xcompmgr). So, basically running xcompmgr in the background does the trick. I even don't get 100% CPU usage when moving windows rapidly - it goes up to around 80%.

And it seems to be OK at this moment! No trails, no strange display problems...

But we shall see if there are going to be stability problems (hope not)