When loading a folder which contains around 500 video files (each approximately 200mb-700mb in size), Finder becomes unresponsive and displays the beach-ball. 

The folder in question is a networked folder (on an AvidISIS server). Network speed shouldn't be an issue as we are accessing the server using dual ethernet cards (high-end).

What's annoying is that this only occurs on systems running Snow Leopard. Our Lion systems (which dont even have the dual ethernet set-up) have no problem accessing the folder. I've also tested this on SL computers without the dual ethernet and the issue still exists.

Furthermore, if I open the folder, wait 10 seconds and then scroll around with the mouse, the folder responds fine for a while. But if I click and drag the scroll bar Finder shows the beach-ball again. 

* Is there a way to prevent Finder from slowing down when accessing the
folder?
* Could it be due to Finder trying to load thumbnails of
the video files?

*(both the Snow Leopard and Lion systems are fully up-to-date - mix of Mac Pros and Mac Minis)*