I'm running only 2 of 4 cards, numbers 1 and 3 (numbering 1-4 from left), but with this setup
I'm getting temps in the 66-71 range. These are the "open" style ones, right? (Sapphire 100282 Xtreme)
Yes those are open type only.
You using 5850 card which may be giving less heat & less hash. Also you have placed with more than 2 inch gap, that gives enough space.
I also think your room temperature & city temperature is in the range 20C.