For the most part, no. In most configurations only digidesign cards are to be installed into the expansion chassis. The only possible exception to this is the following: in a 13 slot expansion chassis, the very last slot of the chassis may be used to install a non-bus master PCI card*. This would be possibly a video card for a second monitor (NOT a video capture card). However, please be aware that this is not guaranteed to work. The more powerful the card is (such as a 3D graphics card), the less chances that it will work, as it will take up too much bandwidth from the PCI bus in the expansion chassis. If you have problems in your Pro Tools system with a non-digidesign card installed onto the last slot, the first thing you should do is to remove this card. * "Bus-master" is a type of PCI card that controls more aspects of the PCI slot than regular PCI cards. Usually, SCSI cards, Video Capture cards, and Network cards are bus-masters. To find out for sure if a PCI card is a bus-master, consult the card's documentation or call the manufacturer.