SIMS 2 Fps ...

Hi All

Just a question about the Sims 2 game. My brothers missus loves this game and has been playing it about 2 years. Their last graphics card was an Ati Radeon 9200 SE, which obviously ran the game (in lowest detail) at about 5 FPS. She didn't mind and still played it. I just gave them my old card, a Geforce 6200 128MB AGP8x. After installing the drivers etc. Far Cry ran smooth as silk, Doom 3 gave about 20 fps (over 5 fps with Radeon), but Sims 2 has NO improvment apart from better graphics. Does anyone know why it hasnt at least doubled the frame rate?

The PC specs are as follows to the best of my memory ....

ATHLON TBIRD 1300MHZ
ASUS SKT A MOTHERBOARD (AROUND 2001)
786MB PC2100 DDR RAM
GEFORCE 6200 AGP (UPG. FROM ATI 9200SE)
80MB 7200RPM ATA133 HARDDRIVE
8X DVD-ROM DRIVE