Windows on mac and video crad

Hi guys i have mac pro 2009 running windows 7 my question is can i have original video card for osx that come with mac and one more video card for windows. Reason i am asking is i am ruining Sidefx Houdini program and it needs better video card then what i have now is NVIDIA GeForce GT 120 and its slow. So i would liek to have one for man and one for windows.

Thanks

You can install only Macintosh compatible video cards in your Mac Pro...AND...a video card you choose must be compatible with a 2009 Mac Pro.

Two cards I know with work with your 2009 Mac Pro:

ATI Radeon HD 5770 Graphics Upgrade Kit for Mac Pro (Mid 2010) - Apple Store (U.S.)

ATI Radeon HD 5870 Graphics Upgrade Kit for Mac Pro (Mid 2010 or Early 2009) - Apple Store (U.S.)

- Nick

can they be any more cheaper.

Unfortunately, quality video cards for the Mac are more expensive than their Windows counterparts. You can shop around on eBay if you prefer but be careful you don't buy a Windows video card that has been "blown" with Mac firmware to make it work. Sometimes they work, sometimes not.

sadly the 5770 is going to be about your cheapest option. the next step up would be NVIDIA Quadro 4000 Professional Graphics PCI-Express Video Card for the Apple Mac Pro.
and it goes for around 1000 bucks american. sorry