Don't know if it's a heat issue. But I did have the 598 right next to the 568.2 with both chassis touching. In my new setup, I have the 598 on a shelf by itself sitting below the 568.2 with at least 6" of space above it to the shelf with the 568.2 and the front/sides/back entirely open. We'll see if heat is the case. I think I'm approaching about one year with the current power supply.