The
Compared Spec for each card shows the Geforce4 Ti4200 as slightly better than the Radeon 9250, but it's only an AGP 4x card whereas the 9250 is an 8x card. Since both are lower end cards, it's shouldn't make a difference as neither will saturate the bandwidth.
However, since you already have the Radeon 9250, I would not spend any money changing out the card.
-Wolf sends