I would move the GPUs around, but the heat problem is likely a result of my setup. I have all of my rigs in my basement covered with a tarp, and air is circulated from outside with an in-line fan which exhausts the air. The GPUs closest to the wall tend to get hotter than the others, and those are the ones overheating when mining Erg.
I appreciate the advice. Hopefully I’ll be able to figure this out.