This is your motherboard.
http://www.nec-computers.com/support2/pib.asp?platform=spec_callisto2g&mode=default&..
PCI-E revision not specified, so it should be 1.0
Technically any PCI-E graphics card will work in it, although a board that old might not recognize a much newer card.
The type of graphics ram (GDDR) the card can use is not affected by the PCI-E slot.