Diagnosis
A firmware update can sometimes reset optimized settings or introduce a temporary high CPU load as it re-indexes or re-analyzes traffic for features like AiProtection.
How to Fix It
Give it 24 hours. Seriously. After a major update, the system often runs background tasks like updating threat databases and scanning network devices. This high CPU usage should settle down on its own. Avoid making other big changes during this period.
If That Didn't Work
If it's still slow and high-CPU after a day, try a simple power cycle: unplug all nodes, wait 30 seconds, plug the main router in, wait 2 minutes for it to boot fully, then plug the other nodes back in. This clears the system's temporary memory (RAM) and can stop any stuck processes.
Heads Up
If you have a lot of devices (50+), the traffic analysis is heavier. You might consider turning off Traffic Analyzer and Adaptive QoS if you don't use them (in the web interface under Adaptive QoS). This can reduce CPU load.