I was just having a similar issue yesterday running a single blade on a back plane with an HP power supply.  I was worried it was the heat and maybe I fried the board or something.  Mine were actually restarting every 2 minutes or so.  I tried all sorts of changes like BFGMiner, different pools, ect...  Finally, I shut everything down for about 4 hours to fully cool and when I restarted, same issue. 

Then I stumbled across this post https://bitcointalk.org/index.php?topic=306556.0 that mentioned problems with wireless.  So I then disabled the wireless on my Att Uverse gateway.  Once I did that, it started working again perfectly.  Been up for about 10 hours now solid.       

Based on the time that the proxy started to slow, it matches with when my wife came home and when her cell phone would have connected via wifi to our home network.  I was able to run a smart TV and my cell phone during the day with no issues, but they were connecting to a second wifi network on another router that is connected to the Uverse gateway via network cable.  So my conclusion is that I can not run the wireless on the same router/gateway that the blades are plugged into.  It is possible this is a problem with the phone and the constant connection, or maybe a setting could be changed in the gateway.  I am open to suggestions, but for now just disabling the wifi got my blade back to full strength.
Good Luck.