Video card problem, don't know where to plug SPDIF-pin and GND-pin on motherboard?

I bought a Nvidia gt9400gt md512 video card from newegg.com. Initially I was told I did not need to hook up the little cable that came with it. I've been a little bit dissapointed in the performance of the card so upon troubleshooting the problem, I read that I DO need to hook up the little orange and black wires. The instructions state under "Enabling HDMI output" "Use the compliant SPDIF internal cable to connect both the SPDIF connectors on the VGA Card to your mainboard. Make sure to (1) plug the orange cable into the SPDIF-pin and the black one th the GND-pin on the mainboard: and (2) plug the other end into the VGA card...............". It goes on to say that if you plug it into the wrong spot on the mainboard you can ruin the card. I can not find where on the motherboard I need to connect these two wires to. I've been all over google and Dell and can't find anything. The computer is a Dell Optiplex GX280. According to belarc, the motherboard is made by Dell, and is a 0G8310. I really could use some help on this. Thanks a lot!|||The reason why your card has disappointing performance is NOT because you didn't hook up the SPDIF audio, which is merely sound output through the card's HDMI port.



The reason why your card has disappointing performance is because the 9400GT is a VERY weak card. Its GPU has all of 16 stream processors.



In comparison, the gamer card in the GeForce 9-series family, the 9800GTX+, has 128 stream processors.



You bought a POS card, that's why its performance is disappointing.|||From viewing the layout of the motherboard in your computer on the following page, I can't see that your motherboard actually has an SPDIF header. i.e. there's nowhere to actually plug the lead from your graphics card.|||SPDIF is for enabling digital sound through your HDMI connection.

Since you have a Dell motherboard, you will need to find the SPDIF connection on your motherboard. The location of all connections are easy to find on aftermarket boards, and the manuals they come with, but, since it is a Dell, you probably do not have any such manual showing you the layout of the board.

I went to Dell's support website, selected Optiplex GX280, then manuals, and found the motherboard layout.

It lists no SPDIF connection.

http://support.dell.com/support/edocs/systems/opgx280/en/ug/smtabout.htm#wp1051997

Dude, you got a Dell.

You have two options, forget about running the sound through your HDMI connection (not a problem if you run your sound through a stereo instead of the HDTV).

Or you can get a sound card (most all have an SPDIF connector). You may have to disable your motherboards integrated sound if you buy a sound card, as well as plugging your speakers to the sound card. They're fairly cheap these days.