I wouldn't mind if they were the same and overclocked as long as they were hashing at 19.3GH while still under warranty. The freq tab says "Default Setting" and the kernal log shows it running them at 487M, which if my math is right would be around 5750 per board?
It affects my performance when I get that temp read error, my hashrate drops to 11.6 GHs when one of the boards show errors, it's happening daily to at least one of the boards.
My guess would be the temperature is pretty high. Where I keep it, the temp is around 10C. With the same frequency as yours, I don't get temps over 63 on any of the boards.