I recently started having severe packet loss and latency problems in every online game. Before this, I consistently had low ping and 0% packet loss, but since one Monday I've been lagging badly and sometimes losing more than 5,000 packets in a single game. I've already replaced the router, fiber jack, motherboard, and Ethernet cables, and even upgraded my bandwidth, but nothing has helped. What should I test next to determine whether the problem is on my network, my computer, or with my internet provider?
2 Answers
First, check whether the problem affects just this computer or every device on the connection. When the issue occurs, test another computer, phone, or console. If multiple devices are affected, the problem is more likely with the provider, fiber connection, or upstream network. If it only happens on one device, check its Ethernet port, drivers, network adapter, and local software. Your provider should also be able to test the line and look for errors or instability.
Run two ping tests at the same time while the problem is happening: one to your router’s local IP address and another to a reliable public address such as 8.8.8.8. If the router ping also drops packets, the issue is inside your home network or on the local connection to the router. If the router stays stable but the public address loses packets, the problem is likely beyond your network and your provider will need to investigate it.
I tested both. The ping to my router was stable, but the test to 8.8.8.8 showed packet loss, so I’m leaning toward an issue with the provider or the connection outside my home.

I’ve replaced several computer components already, but I’ll compare the connection on other devices and contact the provider if they show the same problem.