The Refinery was always the map with worst performance for me. Other maps are very good.
I try a local play today in single player to test it and after patch 1.1.4, Im experiencing a huge frame rate drop next to point D playing with Security, like drops from 67 to 13fps. I didnt have these great drops before.
The rest of the map is not so bad, but when Im using scope(not pip) the frame rate drops a bit too.
Other matches I played online in other maps was all good.