creating cross section is very slow in ORD

Creating Cross Section is very slow in ORD to a point of bordering on timewaste???

we currently have 11km ORD project broken into 5 corridors, then we go and create / draw cross section at 20m interval (577 cross section) with only design and existing DTM.

This is currently taken 3.5 hrs.....yes everyone 3.5hrs, if I was doing this in MX is would take 30 secs.

Has any one some tip/trick on how to reduce this time by a least 1000%, as 3.5hrs is very frustrating …….currently using version 10.07.03.18.