Comparing AGP 8X graphics cards.?

I currently have a craptacular Nvidia Geforce 5500, that I want to upgrade to the highest possible card. I have 3 PCI slots, and I believe that I can run a Nvidia Geforce 6200 at best. The 6200 requires AGP 8X, and my diagnostics test does not say if I have a 4X, or 8X. My question is, can I run the card?