Review RSS CPU distribution before tuning a web server network adapter

Source facts

Microsoft describes adapter offloads as transferring processing work from the CPU to network hardware and lists checksum, large-send, and receive-side-scaling capabilities. For web servers with fewer adapters than logical processors, RSS can distribute requests from different connections across processors. Microsoft warns against mixing RSS-capable adapters with adapters lacking RSS on one server. Microsoft identifies NUMAStatic as the default RSS profile and advises reviewing profiles against the hardware and network environment before selecting one. Microsoft documentation.

Applicability

Use this review for a Windows Server network-adapter tuning decision. Identify the adapter, driver, processor topology, current RSS settings, and representative web workload. Confirm the capabilities actually exposed by the installed hardware.

DSE recommendation

Record the existing profile and processor observations before changing settings. Ask the workload owner to select a representative connection pattern and performance objective. Change one approved setting at a time, keeping the traffic conditions comparable. Include the server’s other processor-consuming work in the observation and preserve a supported path back to the original adapter configuration.

Verification

Inspect the active settings after the change and repeat the agreed workload. Compare request response, throughput, and processor distribution over the same interval. Record any improvement together with its hardware and traffic conditions. Investigate regressions or unstable results before reusing the setting on another server or adapter model.

Official references

Microsoft Learn: Network Adapter Performance Tuning in Windows Server. Source reviewed September 8, 2026.