I think my issue is fixed with idrac7 FW 1.37.35. There was a memory leak which was fixed. I ran "racadm racdump" and looked for memory usage deltas.  
We have a random issue with idrac7 (R620s) where the idrac becomes almost totally unresponsive but magically seems to fix itself within 24 hours. Here is what we have observed:  Has anyone else seen this?  I dont have an SR open but have been in contact with Dell IPS. 
idrac7 goes unresponsive