Connect3D ATI Radeon X 800 XL graphics card.

I've replaced my Creative GeForce 4 Titanium 4400 AGP 4 128MB RAM graphics card with a Connect3d ATI Radeon X 800 XL AGP 8 with 256MB Ram. I've removed the old card's drivers and installed the latest ATI 5.7 drivers.

My 3DMark03 benchmark has increased 10 fold but when I run MS CFS2, MS FS2002 or MS FS2004 my frame rates have actually decreased, though I have left the games' settings largely untouched. The only way that I can get the FR even into the 20's is to switch off all weather, and exterior views of the aircraft are in the low teens.

Could this be caused by installing Dx9c?

I would be grateful for other peoples' experiences with this card.