You need a compatible computer with an AGP Quartz Extreme or PCI Express graphics card to install Final Cut Pro 5.
It's possible to add additional graphics cards after installing Final Cut Pro. If you do this with the intention of enabling an additional display for use with Final Cut Pro, be sure that the additional graphics card is one that is capable of supporting Quartz Extreme.
If you add a graphics card which is not capable of supporting Quartz Extreme technology, Final Cut Pro's windows may not function correctly on a display connected to that card. Final Cut Pro is not supported in such a configuration, and may fail to operate as expected.
302671: "Final Cut Pro supports up to two displays at a time"