Piriform highlighted the improvements of Performance Optimizer in a blog post on the official site.
Several of the listed programs act on their own without user interaction this is the case for all browser updates, e.g., Mozilla Maintenance Service or Google Update, but may also be the case for Microsoft OneDrive, depending on how it is used. It is unclear whether all programs are capable of functioning normally while in sleep mode. Keyboard shortcuts, for the screenshot tool PicPick, worked as usually, while the program was put into sleep mode. Programs that were put into sleep mode responded immediately to user activity.
Performance Optimizer disables 'all startup items, background tasks, scheduled tasks, and services' when a program is put into sleep mode.
