Dedicated capture card vs graphics card?

[manchest72]

I am trying to understand the difference between a capture card and graphics cards and whether or not I need a capture card such as the Black Magic Intensity or whether my planned video card, the ASUS Radeon 4870, would serve the same purpose.

The Black Magic card claims true HDMI digital connections, but the ASUS card also claims HDMI I/O. I am inclined to guess that there is a reason why a separate capture card exists and that it offers better quality than a graphics card, but would appreciate if someone could explain it more.

I hate to add another cost to my future computer, but I do plan on doing animation with AnimatorHD direct into the computer and want the best result I can get.

Thanks for any help.

 

[yh125d]

A capture card and a video card are different. A video card renders video and sends it out to a monitor/TV. A capture card has inputs for video, which it can save to your computer, ala TV tuners, which allow you to record TV to your HD