USCIS Processing Time as of 02/15/2018
USCIS generally process cases in the order they receive them. The link below provides you an estimate of how much time the office handling your case currently takes to process your type of application, petition, or request.
USCIS Processing Time Information
Thanks to Leila for doing a wonderful follow upon RFE for the EAD. I got my EAD approved very soon after an RFE was issued.