Are you talking about APM (Action per minute) ?

Most job aren't crazy when it comes to APM.
BLM has one of the slowest rotation and no crazy opener, RDM is very friendly too.
If you aim to play ranged, DNC would be your best bet.
If you aim to play melee, DRG is the most friendly.

Avoid SAM, MNK, MCH and BRD, they might go a bit fast for you.