Does Microsoft Oulook "load" .ost files when the program is first started? I know that it loads the .pst file and that a bloated .pst folder can cause a very slow start. Not sure if it's necessary to trim down the .ost files too.

And does anyone know WHY Outlook has to "load" these files at start up? I have 3 years worth of emails in my Netscape mail but that never slowed down the launch of the program. Doe does Outlook load these files into RAM memory?