If you’re experiencing a slow-down while using Adobe Photoshop, you may be thinking you need more RAM (always a good idea!), but there’s a chance that isn’t the problem. Thankfully, Adobe offers an easy way to help you decide if more RAM is necessary for a better user experience.
At the bottom left of Photoshop CS5 and CS6’s window is an indicator that can display all sorts of information. Among file size, color profile and save progress, is one called Efficiency. You can click the flyout window arrow and choose Efficiency to get the indicator just to the left (see the image below).
If you’re lucky, it will always say 100%. Anything below 100% indicates that Photoshop has used all its allocated RAM and is using your hard drive as a scratch disk, thus slowing it down. You can allocate more RAM to Photoshop in the preferences, but if memory serves me, Photoshop allocates around 60-70% of your RAM by default. Any more than that and you’re likely to start having problems with the rest of the system. If the Efficiency Indicator displays anything below about 85-90%, I would highly recommend investing in more RAM.