Inactive Memory Problem With Photoshop CS6

By | July 19, 2012

I’ve been scanning several hundred postcards from the early 1900s recently. I’ve scanned them at as high a DPI and colour depth as I can to try to make the images as useful as possible in the future.

Each image is about 1.2Gb. I’ve been editing each one in Photoshop CS6 to correct rotation, crop out whitespace, etc.

I found that I can edit about a dozen images before I see a gradual slow down of my iMac, until after a few more edits it is almost unusable.

When this happened last time I checked Activity Monitor and noticed that I only had 700Mb of RAM free, while I had 6Gb of ‘inactive’ RAM.

FYI, I was doing this on a Core i7 iMac with 12Gb of RAM and 500Gb of free disk space.

Googling around a bit revealed that I could remedy this inactive RAM problem by rebooting, or by running the following in a Terminal window:


This frees up inactive RAM, and makes it available to the iMac again. Once I did this everything sprang back into life.

Update: I find that Adobe Bridge CS6 is a bigger cause of this than Photoshop CS6.