Reddit mentions of StarTech.com 6in Stereo Audio Y-Cable - 3.5mm Male to 2X RCA Female - Headphone Jack to RCA – Computer / MP3 to Stereo 1x Mini-Jack 2X RCA (MUMFRCA)

I use an ultra basic setup to connect my LSR305 to my desktop PC which does not have a dedicated sound card (motherboard audio jack only).

I plug a 3.5 mm to stereo RCA female into the motherboard's audio jack and then use these RCA male to 1/4" TS male cables to connect to the speakers.

I don't know if I've ever seen a gpu with any kind of video input. I'm not saying that they don't exist, but I've never heard of it. Honestly, I think OP is confused on what he's looking for.

OP, why do you want to plug in a console into a GPU rather than a monitor? If the goal is to get the console on a monitor, you'll need some kind of capture card (that accepts what your console outputs) and software or just an upscaler hooked up to the monitor.

I recommend getting an upscaler unless you're trying to record yourself playing. The problem you might have is getting one that can separate video and sound since your monitor doesn't have hdmi.


Edit: Probably the easiest thing that would work for you is getting something like this:

http://www.amazon.com/Mini-Composite-CVBS-Converter-Input/dp/B00I482KZI/ref=sr_1_1?s=electronics&ie=UTF8&qid=1457981421&sr=1-1&keywords=composite+to+hdmi+upscaler

Since your monitor doesn't have hdmi, you'll need a hdmi to dvi cable like this:

http://www.amazon.com/Mini-Composite-CVBS-Converter-Input/dp/B00I482KZI/ref=sr_1_1?s=electronics&ie=UTF8&qid=1457981421&sr=1-1&keywords=composite+to+hdmi+upscaler

For sound, you'll need to figure out if you can send the red and white cables to your speakers. Do your speakers have a stereo or rca jacks? If they don't, you'll probably have to convert the rca to stereo:
http://www.amazon.com/gp/product/B000A88L9E?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

and get a stereo coupler like this:
http://www.amazon.com/Monoprice-107230-Stereo-Adaptor-Plated/dp/B004C87WQ6/ref=sr_1_1?s=electronics&ie=UTF8&qid=1457981876&sr=1-1&keywords=stereo+coupler

This is what you need. Only stereo though, if you want 5.1/7.1 you'll probably need a better sound card.

I bought mine from Radio Shack, if you don't want to wait for it to get shipped. I kinda like the kind with female RCA ends on it though so you can just get a couple long male/male RCA cables. Because of the length you are talking about you will probably require some adapters if you go with the male/male version.

You would need female rca connectors: http://smile.amazon.com/StarTech-com-MUMFRCA-Stereo-Audio-Cable/dp/B000A88L9E/ref=sr_1_1?ie=UTF8&qid=1465171109&sr=8-1&keywords=rca+female+to+headphone

You should be able to plug your red and white cables right into that and everything should work.