[PIF]

Adobe Photoshop Lightroom 3 is a professional level image cataloging application. And it needs a LOT of RAM. Any bugs are Abobe’s not Apple's in this situation.

The larger the catalog one is working with, the more RAM needed. A high end graphics card also helps.

For large catalogs, either use the high-end iMac with the best card available and max RAM, or a MacPro also trickled out.

Look here
Optimize performance | Lightroom
http://kb2.adobe.com/cps/400/kb400808.html

[mass55th]

Thanks for the info.