imac slowed down by my display link
 

I am currently running an imac 27 inch, late 2009 with 4 gig of ram and a 3.33 ghz intel core 2 duo processor.

I have connected the newertech displaylink which goes from my usb 2.0 port and converts to DVI, into vga. When I connect the displaylink, it instantly slows down my mac so that all video runs jittery.

Is there any known solutions to this problem?

I am running osx 10.7.1, and I have all the up to date displaylink drivers.

I would appreciate any help.

Thanks!