Speed Up Photoshop File Saving by up to 20X
Photoshop is single-threaded for compression while saving files.
To speed up Photoshop saving and opening by up to 20X, make sure that
is checked.By so doing, the gating factor of compression is avoided; the save or open is thus I/O bound (limited largely by the speed of the drive).
The faster the drive the greater the benefit, such as on the blazing fast flash drive (SSD) in the late 2015 iMac 5K.