So if you want my opinion on the subject, if the nouveau driver is working and with 3D support, I would stick with it. I have decided to use it with my GT 275 card and it works properly in every way. Consider that you can up the kernel version, to 3.6.2 if you like, where the nouveau driver is located. I am running 3.6.2 right now from kernel.org and it seems to work very fast for me. If you have not seen my bash script to load new kernel versions, have a look here:
One of the issues you can have is an xorg-x11-server update, it replaces some stuff from the nvidia driver. Reinstall the nvidia packages and have another look at the FPS.
I wouldn’t bother too much, glxgears isn’t a benchmark, if it shows 60 fps it just means it’s synced with your monitors refreshrate, there are some advantages with that. You can change this behavior in the settings, just open up Nvidia xserver settings, go to OpenGL settings and tick off Sync to VBlank.
I’m away for 4 days, so I can’t tell you what version the NVIDIA driver on 11.2 is. I tried installing an older version by downloading it from the NVIDIA web site, but the install failed. It was not compatible with 12.2.
Personally I would uninstall nvidia, update xorg, reinstall nvidia. nvidia does replace some original files so after upgrade of xorg nvidia complaints that installation is corrupted so who knows whether it will be able to really uninstall it (or what happens in this case).
This conflict only happens if you install the driver “the hard way”, the packaged driver in the repo avoids this and installs the libGL stuff under /usr/X11R6 instead of under /usr/lib or /usr/lib64 where the original xorg stuff resides. Jerryrc used the repo driver and intends to stay so.
The desktops in 12.*, be it Gnome or KDE, are far more demanding on the hardware, so no need to worry there. And do toggle that switch Sync to VBlanc on again, 60 fps is what your display can do at 60 Hz, anything above that is just theoretical.
