I know it seems odd, but these mining chips do like to run a little warm. I ahve found that if I let the board temps get under 60c on the S7s they actually start to become unstable and crash a lot more than expected. Avalon 6 miners are the same way, under 60c and they see a noticable hash rate drop. I have personally found with the s7 that the sweet spot is 65-70c.