Depends on why it is freezing. If you are running a lot of PCI cards, and your board is too old to support PCIe or even AGP... there isn't much you can do. You only have so much bandwidth to deal with, and running a video card from plain old PCI... it will try to hog all the resources, and your other PCI cards will be hungry... hence it will freeze or stall because of IO and bandwidth requests.
What motherboard are you running? What is your CPU, how much RAM do you have? Something else might be causing the freezing.