I was experiencing some lock-ups and performance issues with the previous 275.09.04 beta driver, but not nearly as bad as the nvidia-current driver currently in the natty main repository.

I have been running the new 275.09.07 driver all day without any issues thus far.

The new beta 275.09.07 is available via a ppa, with
add-apt-repository ppa:xorg-edgers/ppa
Please read the pages at https://launchpad.net/~xorg-edgers and https://launchpad.net/~xorg-edgers/+archive/ppa, this repository is descried as:
Go break your X here: https://launchpad.net/~xorg-edgers/+archive.
See https://wiki.ubuntu.com/XorgOnTheEdge for a script that installs and runs the test packages in a live CD/media session, for quick and easy temporary testing.


Most of you will want the nvidia-current i386 or amd64 package and perhaps the nvidia-settings package.
For direct downloads:

https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-current_275.09.07-0ubuntu1%7Eedgers%7Enatty_amd64.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-current_275.09.07-0ubuntu1%7Eedgers%7Enatty_i386.deb

https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-settings_275.09.07-0ubuntu1%7Eedgers%7Enatty_amd64.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-settings_275.09.07-0ubuntu1%7Eedgers%7Enatty_i386.deb

https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-185-kernel-source_275.09.07-0ubuntu1%7Eedgers%7Enatty_amd64.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-185-kernel-source_275.09.07-0ubuntu1%7Eedgers%7Enatty_i386.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-185-libvdpau-dev_275.09.07-0ubuntu1%7Eedgers%7Enatty_amd64.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-185-libvdpau-dev_275.09.07-0ubuntu1%7Eedgers%7Enatty_i386.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-185-libvdpau_275.09.07-0ubuntu1%7Eedgers%7Enatty_amd64.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-185-libvdpau_275.09.07-0ubuntu1%7Eedgers%7Enatty_i386.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-current-dev_275.09.07-0ubuntu1%7Eedgers%7Enatty_amd64.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-current-dev_275.09.07-0ubuntu1%7Eedgers%7Enatty_i386.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-glx-185-dev_275.09.07-0ubuntu1%7Eedgers%7Enatty_amd64.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-glx-185-dev_275.09.07-0ubuntu1%7Eedgers%7Enatty_i386.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-glx-185_275.09.07-0ubuntu1%7Eedgers%7Enatty_amd64.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-glx-185_275.09.07-0ubuntu1%7Eedgers%7Enatty_i386.deb
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-graphics-drivers_275.09.07-0ubuntu1%7Eedgers%7Enatty.diff.gz
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-graphics-drivers_275.09.07-0ubuntu1%7Eedgers%7Enatty.dsc
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-graphics-drivers_275.09.07.orig.tar.gz
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-settings_275.09.07-0ubuntu1%7Eedgers%7Enatty.diff.gz
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-settings_275.09.07-0ubuntu1%7Eedgers%7Enatty.dsc
https://launchpad.net/%7Exorg-edgers/+archive/ppa/+files/nvidia-settings_275.09.07.orig.tar.gz