Hi, as stated here:
The cairo-1.10.0-buggy_gradients.patch shouldnt be needed anymore,
but i tried unpatched cairo 1.12.8 with nvidia drivers 310.14(beta),
304.60 and 304.51.
With those drivers gtk applications are very slow, even firefox is
slow when scrolling pages using native widgets.
Applying the cairo patch OR using nouveau make things smooth again.
Bug report rejected by Arch developers:
Nvidia bug report