Comment 143 for bug 948053

Thanks Colin! Works for me: (Note: I've not tried with Unity as it's not supported with this card/driver)

$ sudo lshw -C display
  *-display
       description: VGA compatible controller
       product: NV25GL [Quadro4 900 XGL]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:01:00.0
       version: a3
       width: 32 bits
       clock: 66MHz
       capabilities: pm agp agp-2.0 vga_controller bus_master cap_list rom
       configuration: driver=nvidia latency=248 maxlatency=1 mingnt=5
       resources: irq:16 memory:fd000000-fdffffff memory:d0000000-d7ffffff memory:dc780000-dc7fffff memory:fe9e0000-fe9fffff

$ jockey-text -l
kmod:martian_dev - Agere 164x dsp driver (Free, Enabled, In use)
xorg:nvidia_96 - NVIDIA accelerated graphics driver (Proprietary, Enabled, In use)

$ apt-cache policy nvidia-96
nvidia-96:
  Installed: 96.43.23-0ubuntu0.1
  Candidate: 96.43.23-0ubuntu0.1
  Version table:
 *** 96.43.23-0ubuntu0.1 0
        500 http://us.archive.ubuntu.com/ubuntu/ precise-proposed/restricted i386 Packages
        100 /var/lib/dpkg/status
     96.43.20-0ubuntu6 0
        500 http://us.archive.ubuntu.com/ubuntu/ precise/restricted i386 Packages

$ /usr/lib/nux/unity_support_test -p
OpenGL vendor string: NVIDIA Corporation
OpenGL renderer string: Quadro4 900 XGL/AGP/SSE2
OpenGL version string: 1.5.8 NVIDIA 96.43.23

Not software rendered: yes
Not blacklisted: yes
GLX fbconfig: yes
GLX texture from pixmap: yes
GL npot or rect textures: yes
GL vertex program: yes
GL fragment program: no
GL vertex buffer object: yes
GL framebuffer object: no
GL version is 1.4+: yes

Unity 3D supported: no

$ glxgears
Running synchronized to the vertical refresh. The framerate should be
approximately the same as the monitor refresh rate.
10114 frames in 5.0 seconds = 2021.769 FPS
10893 frames in 5.0 seconds = 2178.501 FPS
10874 frames in 5.0 seconds = 2174.723 FPS
10618 frames in 5.0 seconds = 2112.233 FPS

Previous driver installed was the direct NVIDIA-Linux-x86-96.43.23-pkg1.run, so I've been able to easily compare performance.
96.43.23-0ubuntu0.1 went in without any problems at all. Thanks again!