Symptoms

On AMD PowerEdge R7625 systems with minimal memory installed, GPU workloads may degrade over time due to NUMA-related inefficiencies. The NPS=0 BIOS setting, which can help lessen this, may not appear under certain configurations. BIOS configuration on AMD R7625 systems does not show NPS=0 as a selectable option.GPU workloads initially perform well but degrades after ~20 minutes.Performance degradation happens when memory usage crosses NUMA boundaries.BIOS error UEFI0391 may appear when memory is not fully populated.

Cause

The NPS=0 option needs a balanced memory population across all memory channels. Systems with fewer than eight DIMMs (4 per socket) do not meet this requirement, preventing NPS=0 from appearing in BIOS. This leads to inefficient NUMA configurations and degraded GPU performance under memory pressure.

Resolution

To enable NPS=0 and resolve performance issues: Install at least eight DIMMs (4 per socket) to meet the balanced memory requirement.Ensure both CPUs are detected during POST. A missing CPU can hide NPS=0 from BIOS.Update BIOS, iDRAC, and CPLD firmware to the latest available versionsVerify NPS=0 availability in BIOS or using iDRAC after memory upgrade.Enable NPS=0 For the best results, follow these published configuration guidelines: NVIDIA Certified Configuration Guide : Recommends system memory be at least twice the total GPU memoryDell EMC Balanced Memory Guide - AMD EPYC: Explains balanced configurations satisfy NPS 0/1 conditions by requiring that each memory channel is populated with identical DIMMs. Dell NUMA Configurations for AMD EPYC: States NPS=0 configures memory interleaving across all 16 channels in dual-socket systems.

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