I got 105 fps with my Magic Pro Geforce2 MX400
(Driver : 6.5 ship with the card )

Now I got 70 fps with my new WinFast Geforce2 GTS
(Driver : 6.48 download from Leadtek.com )

My setting is almost the same among two cards.
Vertical sync : disable
FSAA : disable
Graphic quality : highest
1024x768x16bits
Windows ME, Pentium III 533EB

Although the fishes swim as smooth enough.
I don't know why it yield a such strange FPS.