NVIDIA HGX H100 8-GPU Baseboard Diagnostics
Classification: Enterprise AI & High-Performance Computing Equipment
Hardware operational fault codes, protection alarms, LED blink sequences, and step-by-step diagnostic fixes for the NVIDIA HGX H100 8-GPU Baseboard.
Indexed Fault Codes for HGX H100 8-GPU Baseboard
Step-by-step resolution manuals and root cause matrices
NVSwitch Routing Credit Timeout
SXid 63 indicates a fatal port routing credit starvation timeout on the NVSwitch crossbar fabric. An NVLink endpoint failed to return flow-control credits within the hardware watchdog window, deadlocking fabric routing and triggering kernel-level GPU isolation.
NVSwitch Port Link Training Abort
SXid 62 designates an NVLink physical layer (PHY) communication breakdown where high Cyclic Redundancy Check (CRC) error rates prevent link training or cause an active link to abort during link negotiation between a Hopper GPU and an NVSwitch.
NVSwitch Link Integrity NCCL Timeout
SXid 120 denotes a critical physical layer (PHY) or data link layer integrity failure on an NVLink connection between an H100 GPU and a 3rd-generation NVSwitch ASIC. When excessive symbol errors, flit CRC corruption, or lane degradation exceed threshold tolerances, the fabric drops packets, resulting in an unrecoverable NCCL all-reduce kernel timeout.