Adding another 512 gb RAM will keep Pro from using the Page file, which can slow things way down on larger projects. I would not try to do serious editing with only 512.
Another video card (Nvidia 128 MB) will help with GUI redraw issues (Pro’s interface gets funky with bits of the desktop showing thru and window trails, etc.). Also having a card with Open GL will give you a few more effects in Pro.
Windows will prevent you from opening any file that is open on another computer,except as “Read only”. The message will tell you who is working on the file.
There are other issues when using source video files stored on a network server involving lack of response and poor previews…stuttering, etc.
Timeline renders are for previews only and have no other function, excpet some use these to export to tape. Exporting Mpeg, AVI’s or WMV;s does not use the rendered preview files.