Question : Problem: PCI Express x8 compatible with x16?

I'm building a new system and I am wondering if a PCI Express x8 raid controller card can be used on a PCI Express x16 slot on the motherboard. I have not used any PCI Express or PCI X devices, and it is a bit confusing.

Here are the specific components I'm looking at:
http://www.newegg.com/Product/Product.aspx?Item=N82E16816131006
http://www.newegg.com/product/product.asp?item=N82E16813151056

Answer : Problem: PCI Express x8 compatible with x16?

Yes pci express cards will work aslong as they are smaller or equal to the size of the slots. so pci-e x1 will work in all pci-e x1 x4 x8 x16 slots.  PCI-e x8 will work in a pci-e x16 slot