I've reported this before, but I've now replicated it on two different Storm Overos (IronSTORM/FireSTORM) using two different OS images (both Sakoman console images built using mkcard.sh).
When I set the mpurate to the maximum 1Ghz I start to get periodic Ethernet errors. During an SSH session with the Overo, this shows up most often as a "Corrupted MAC on input" message and a dropped session. Sometimes the SSH session just drops with no message. New connections are accepted, but the drops occur frequently (several per minute).
Setting the mpurate down to 800Mhz (or lower) corrects the problem.
Any ideas here, on how to solve this at the full