Yes lag and setting up speed (less kit to carry) is the point of the PCI card. I didn't find an older version of Modul8 yet, and I still need to raise a support ticket here via e-mail.
I was wondering this morning if it may be due to an updated driver from 5 squared
which does say it was updated to work with osx 10.5 Leopard. Maybe if I could trace and earlier inatance of the driver it may solve the issue. Or did you get your card to work with the latest driver with an older version of Modul8?