Scratch Disks

When Photoshop runs out of RAM it moves the tasks to your hard drive. If you have more than one, you can set the fastest drive as your scratch disk. Use your fastest drive (with free space) as your primary scratch disk and try to attach a second drive as a failsafe in case you run out of space, to avoid the Scratch Disk Full error If you want maximum performance, install an additional SSD drive that you only use for Photoshop, don’t run your OS or other programs from there, not even Photoshop. Set this as your primary scratch disk and you will find that Photoshop runs smoother, particularly for large files or files with lots of layers.