This thread confused me too, so I went looking. This page helps to explain the OP's conundrum: http://www.xlr8yourmac.com/Graphics/mac_6800ultra_review/ .

OP: If you scroll down that page, you get the names of the updated extensions to check against your system. Alternatively, might also be able to find what you need by googling those. The truth is, though, that this seems to have been a problem card.