In my case I had to compare column E and I.
I used conditional formatting with new rule. Formula was "=IF($E1<>$I1,1,0)" for highlights in orange and "=IF($E1=$I1,1,0)" to highlight in green.
Next problem is how many columns you want to highlight. If you open Conditional Formatting Rules Manager you can edit for each rule domain of applicability: Check "Applies to"
In my case I used "=$E:$E,$I:$I" for both rules so I highlight only two columns for differences - column I and column E.