Windows 7 - sound and video card

What would be the minimum amount of space required between a sound and video card?

A sheet of paper?

If I am reading into this correctly, you have, or want to, install a sound card in the slot right next to you video card and are worried about how close together they are.

The answer to that question is that they will function as long as they both fit in their slots without pushing on each other.

But the secondary issue is heat, and whether you would experience any heat related issues would depend on the quality of the cooling system in your case, and how clean you keep it - as dust will build up much more between components that are close together.

No chance of using a lower slot on the board?

Unfortunitly the only slot avalible is right next to the second video card i have installed. there is about 1/4 of an inch between them. I have the thermaltake level 10 gt case and I have the side fan directing air straight on to them.

Nice case! Does it transform into a car?

I don't think you will have a problem.
Do you have a program that will monitor temps for you? Speedfan SpeedFan - Access temperature sensor in your computer is good.

my mother board came with some decent software that showes me mb and cpu temps. No unfortunitly it doesnt transform into a car but I couldnt find another case that I liked once I found this one.

So just monitor the temps in the case, and particularly the video cards. I think you will be fine.

Ditto to TVeblen, the sound card will normally not be a big heat concern anyway...unless you're trying to drive a 14" woofer and a 7-1 sound system. Seriously it will be fine especially with the side fan bringing in cool air.