This may not be much help, if so I apologise. My current setup is a 290 x1, 8350 @4.8Ghz
these are both watercooled in the same loop by a 120(duel thickness) and 360 rads
When i'm gaming on 1920x1080 maxing something like bf4 or titan fall for a few hours, the highest i've seen them go up to is around 39 so far (bearing in mind its fairly cold right now) If I wsa to add another 290 in the loop i'm sure the difference would not be huge.