To effectively diagnose and resolve your Ethernet lag, follow these systematic steps: Inspect the cable for any visible damage, kinks, or a broken clip on the connector. Just got Fiber installed, and down speed is phenomenal but I seem to be getting intermittent lag spikes that make things like gaming worse. What is the reason behind. Your Wi-Fi may be slow due to a number of reasons, including issues with your internet provider, your modem or ONT, your router, or the devices you use. The best way to find the source of your slowdown woes is to run a few speed tests. Identifying the symptoms of a troubled network can help you swiftly diagnose and tackle the underlying issues. You've probably spent more time troubleshooting.