There is a fix for this issue in the newest driver-version :
http://cgit.freedesktop.org/xorg/driver/xf86-video-intel/commit/?id=73db44e7ac524e84e5f0fda2d60069a9e954ad1b
"Drop Legacy3D option, only use fixed texture space with non-gem."
Together with two other git-commits (see Bug #316588) backported to the driver version 2.6.1, the driver now works perfectly on my 855-chipset.
There is a fix for this issue in the newest driver-version :
http:// cgit.freedeskto p.org/xorg/ driver/ xf86-video- intel/commit/ ?id=73db44e7ac5 24e84e5f0fda2d6 0069a9e954ad1b
"Drop Legacy3D option, only use fixed texture space with non-gem."
Together with two other git-commits (see Bug #316588) backported to the driver version 2.6.1, the driver now works perfectly on my 855-chipset.