ATXN-5520 / ATXW-5520 Technical Reference
Motherboard Installation
3-13
Chassis Plans
Processor Thermal Throttling LEDs
When LED3 and LED4 are off, both processors are functioning within the proper thermal conditions. If
either LED is flashing, this indicates that the associated processor is operating at a lower operating speed
because the CPU core has reached a temperature above the processor‟s thermal throttling level. A solid
orange LED condition indicates that the processor has reached a CPU threshold limit. Processor thermal
shutdown may occur if the condition causing the elevated temperature state is not corrected. Refer to the
motherboard status LED section of chapter 1 for more detail. The locations of LED3 and LED 4 are shown
in the diagram below.
CAT LED
LED5 is the catastrophic (CAT) LED located on the motherboard as shown below. This LED comes on of
the processor‟s cannot continue to operate due to non-recoverable machine check or other internal
unrecoverable errors.
