ER 89872 Cisco Bios issue found. From Cisco: "I have an update on this. Today we were able to connect the dots and found that we recently fixed a problem related to interrupt remapping in the VT-d. Apparently, the work around of disabling interrupt remapping may not always solve the problem.
In the past we have seen many different manifestations of this issue, adapter disconnects and sometimes even PSODs.
Contact Cisco to obtain necessary Bios Updates.