It is not true for capturing through firewire because basicly all you are doing is transfering digital information from tape to disc (hard drive). There's nothing in the graphics adapter or sound card that alters the information during a basic capture. It's similar to copying a computer file from one drive to another. The only difference would be that the capture software might scan the incoming data and breaks it up into chunks based on the time stamp. Even then the all information goes through the CPU not the sound or graphics cards. The same with rendering in Vegas. All calculations are made by the CPU for the final project file.

However, it is possible that the editing process (the previews) could be affected by the sound and graphics cards. But in that case the quality of your speakers, computer monitor, and television monitor also play a role. Probably a greater role than the sound card and video card.

JBJones