VMAX 3 FAST - data that could be moved to higher-capacity drives, without affecting existing performance

Hello Folks,

Can any one please tell me how it actually work for the below statement from the below paragraph.

Important line :-

identifying less-busy data that could be moved to higher-capacity drives, without affecting existing performance

Paragraph :-

" Fully Automated Storage Tiering (FAST), automates the identification of active or inactive application date for the purposes of reallocation that date across different performance/capacity pools within a VMAX3 storage array. FAST proactively monitors workloads to identify busy data that would benefit from being moved to higher-performing drives, while also identifying less-busy data that could be moved to higher-capacity drives, without affecting existing performance  ".