I'm thinking about getting an Alienware Area 51 system with a Radeon 9800XT card. Will adding an RTX 100 card cause problems with the system's stability? The sales rep at Alienware thought it might cause crashes or slowdowns, but he wasn't sure. Any idea whether systems can function with gaming and capture cards installed together?

Do you really need such a card? A basic firewire board will work
just as well for capturing DV. Ofcourse such a board does not
have analog connections or "realtime" capabilities.

With that being said I would shoot the people behind the RTX 100
an e-mail and ask them. I can't imagine they are not at least
testing their product(s) with the most important cards on the
market (nVidia & ATI boards). I can imagine they will be able to
tell you if it should work or not.

Considering he's buying an Alienware system, the 9800XT is mostly for gaming use. The 9800pro 128MB is generally a better buy though.

I don't know about the RTX.100 card though. Maybe the Matrox forums would be helpful?