PE 320 Performance on Server 2012

Quick Summary:

Have multiple Dell PE320 servers (both tower and rack) deployed with Server 2012 or Server 2012 R2.

Servers experience a severe performance issue at random intervals (between a few weeks and a month).  CPU usage reports 100% in Windows, although total of running processes is near 20%.   Deferred Procedure Calls show between 3% and 5%.  Services in Windows begin to crash, due to startup timeouts.

Typically, an update of various firmwares (idrac, lifecycle, perc) solve the issue - only to have it repeat again.

This past Friday, it occured the second time on a brand new installation.   Updating of the firmware failed and bricked the iDRAC.   New motherboard on the way Monday.

Last night, while trying to finish up a new deployment;  a new R320 begin exhibiting the same issues.  Recently I realized that all of these servers in question are using USB drives for backup.    Figuring the USB driver may be the issue, I disabled and performed a reboot.

I'm posting this while waiting for it to get to a point to respond to RDP.

These are a mix of configurations:

a:  T320, 6 core 2.0Ghz cpu, 24GB RAM (8x3G).  PERC H310/RAID 1.  SATA drives.

b:  T320, 6 core v2 2.50Ghz, 24GB RAM (8x3G).  PERC H710p/RAID5.  N-SAS drives.

c:  T320, 6 core v2 2.50Ghz, 24GB RAM (8x3G).  PERC H710p/RAID5. SAS drives with 160GB Cachecade.

I have an ongoing ticket, for "B" (the one with a new motherboard on the way) - but this seems way beyond coincidental.   Am I missing something on these deployments?