You know this is a thin edge of the wedge question don`t you?
If you did buy a the card you`d be wondering how much better
it would be if you had an 8X AGP Motherboard. So you have
to get one of those, then of course you`d worry about the
crap CPU you`re left with so you`d have to get a new one of
those. Oh and that slow old memory... better change that too.

there you are...New PC. Two months later and Nvidia brings out
the FXXS6000 Geforce 10 16xAGP Ultra Deluxe and you are
back where you started.

Go for the new PC in a couple of years option.