Comment 2 for bug 629910

Yes I can confirm there is a regression issue with xserver 1.9 (at least up to 1.9.0-0ubuntu4) and nvidia-current (at least up to 256.53).

This is most prominent when scrolling in some applications.
I have found that synaptic is a very good example of this one.
Scrolling is severely influenced there.

With xserver 1.8 branch and nvidia-current 256.44 scrolling was very fluent:
a big difference compared to xserver 1.8 branch with ati open source drivers (xserver-xorg-video-radeon).
Now the open source ati drivers are clearly faster than nvidia-current_256.53 with xserver 1.9.

But, for the time being I cannot say if this is a regression in xserver 1.9 or have certain codes changed in the new xserver so much,
that nvidia drivers ought to be changed as well.
At least it seems not to be a regression in nvidia-current, because the same driver (256.44) works very well with xserver 1.8, but not with xserver 1.9 (with IgnoreABI command).