When thinking about performance, we need facts and figures in order to make appropriate changes. This can be done using Photoshop’s built in Efficient Indicator.
The efficient indicator is part of Photoshops pop-up menu (the menu at the bottom of the image window). Here is how you display the Efficiency Indicator
33. Click on the directional arrow at the bottom of the window (next to the scroll bar) > Select Efficiency
34. You will now see the efficiency displayed in percentage format. As you perform actions in Photoshop, keep an eye on the efficiency indicator. If the number drops below 100%, it means that Photoshop has used all allocated RAM and is using the Scratch Disks. If this happens frequently, change your performance settings. Or in the best case scenario, add more physical RAM to your system.