My board

if the card works in both 4x and 8x mode then a 4x slot should work fine. There may be a performance decrease running the card interface at half speed.

 

8x will work in 4x mobos. but if you havent bought the card yet, i say u dump ur board and get a pciex combo

 

I was thinking this card

PNY GeForce 6200 / 256MB DDR / AGP 8x/4x / DVI / VGA / TV Out / Video Card

 

No No please dont. whatever interface u have AGP or PciEx, dont buy a 6200.
Dont be fooled with tech words such as turbocache or hyper memory. they dont give better quality or FPS. It just means they are sharing precious memory of your system. Unless u r on a very very tight budget, check out the 6600GT 128mb ddr3. Believe me the extra 128 memory on the 256 card doesnt make much of a difference on current games.
the 6600GT is a pretty formidable chipset and it will run ALL games perfectly.
And its a little futureproof !!

 

What about my board

Only being a 4x?

 

A 6200 isn't that bad if you get one that isn't a turbo cache version, and that has a 128bit memory interface(not a 64bit). In any case, turbo cache is only available for pci-e cards, so an agp card couldn't have turbo cache. My 6200 was one of the "special" ones that can unlock to be a 6600, but doing so makes it run hot. I think most newer 6200's cannot be unlocked anymore.
A 6600gt is a good card though, if you can afford it.

If this is the 6200 you're looking at, then I'd avoid it, it's a 64bit(crippled) edition.
http://www.newegg.com/Product/Product.asp?Item=N82E16814133151

You can get a 128bit 6600 for just a little more, or a 6600gt for just a little more than a 6600.
http://www.newegg.com/Product/Product.asp?Item=N82E16814121197
http://www.newegg.com/Product/Product.asp?Item=N82E16814130220