IERR is a Processor Internal Error; it is a signal that indicates a Processor unrecoverable error or even a non-CPU event, such as a System BUS interruption or a memory can start this signal.
On an Intel® Server Board, a Processor IERR can be confirmed of discarded by running a CPU Retest from the BIOS (Basic Input Output System) Setup Utility. This option can be enabled under the Advanced -> Processor Configuration Menu.
In some cases a system restart can also eliminate an IERR but if the problem persists please try to boot up the system with one processor at the time, test another processor if possible and remove and reinstall the memory.
The IERR Filtering Algorithm helps to determine if the IERR signal came from a false CPU internal error or from another hardware source; preventing unnecessary processor replacements and at the same time helps to isolate IERR events.
This applies to: