Hello, I'm building my own computer, I know how to put them together and everything, but I can't figure out why the video card (salvaged from an old compaq presario) in addition to the part where it plugs into the AGP port seems to have a set of pins the same number of pins and the same spacing as the IDE conntroller on my motherboard. It really looks like I could plug an IDE cable in there and hook a hard drive onto it, but I have no idea why I would do that.

The video card supports:
DFP
CRT
TV out

The big chip in the middle of the card has a 3d box with the ATI Logo in it an the markings on the chip say:
RAGE LT PRO AGP
215LT3UA31
B9J1G
9845SS
TAIWAN (figures)

**UPDATE: I tried plugging an IDE cable into it, it's a perfect match, but I still can't figure out what it's for

Here's what I found on the ATI website, in the discontinued section. I can't guarantee this is the same card you have, but it's the closest I could find.
Judging by this, the adapter port on the card sounds like it's the connector for the ATI-TV WONDER card. Back in the day (late '90s), the add-in cards could be connected to the main video card via special cables. The old Voodoo2 cards could be combined this way to double your video performance.

I can't guarantee this is exactly what your card has, but I can fairly comfortably state it's not an IDE connector.

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I would agree with Crystalattice I used to use two monster 3D card that would connect using a cable it was cmaller than a IDE cable, but never the less I believe that this what that connection is used for.

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