nVidia has started supporting older cards like the 9500GT. These won't enable the card from initial boot screen, but they will function normally once the drivers initialize later in the boot process. If you can deal with a dark screen at boot for the first little bit, you'll get complete Core Image/Quartz Extreme support in 10.7.5+ with these newer nVidia drivers on real Macs. These drivers make all cheap PC nVidia cards work on real Macs without flashing, IF you can deal with the dark screen at startup.
For Lion 10.7.5:
<http://www.nvidia.com/object/macosx-295.00.05f03-driver.html>
For Mt. Lion 10.8.4:
<http://www.nvidia.com/object/macosx-313.01.02f01-driver.html>
New versions can be found by Googling for "QUADRO & GEFORCE MAC OS X DRIVER RELEASE"