I recently purchased a well spec'd iMac with 8GB of RAM, on the basis that I would buy 3rd party RAM when I found that I needed it... I need it. Most things run fine but I've finally come across a situation where I need more RAM. In my case it is using Adobe Lightroom to stitch together multiple large (50MB) pictures into a panorama. The activity monitor shows over 7GB of RAM in use and the process is very, very slow. So, having established that I do need more RAM, the next question is how much? Is there any way of determining how much RAM the computer would use to perform a given task if it had more than enough? I don't want to get another 32GB of RAM only to find I should have gotten 64GB (or vice versa).