I've been dealing with unstable internet for about five years. I live in a major city and previously used Spectrum before switching to AT&T, but the problem continued and may have gotten worse. I've tested multiple computers and other devices, all connected by Ethernet, and I've also replaced or changed routers, drivers, and providers.
My latency sometimes stays around 50–90 ms, but it fluctuates for 20 minutes at a time. Then it can jump to 150–800 ms, or even around 1,400 ms. Games become unplayable because I freeze, teleport, and rubber-band. Downloads are also incredibly slow; for example, a game update on another PC estimated that it would take more than a day.
What could cause this if it happens across multiple computers, routers, Ethernet connections, and internet providers? What tests can I run to determine whether the problem is inside my home, with the physical line, or somewhere in the provider's network?
4 Answers
There are still some important details to confirm with the provider: whether the connection is coax, DSL, fiber, or fixed wireless; the advertised upload and download speeds; the modem and router models; and whether the connection shows packet loss or signal errors. Since the issue has continued across different computers and providers, ask the current ISP to check the line and modem signal levels rather than only running a basic speed test.
Run two continuous ping tests while the problem is happening: one to your router’s local address and another to a public address such as 8.8.8.8. If the router ping starts spiking too, the issue is inside your home network, such as a bad cable, interference, a failing router, or bufferbloat. If the router stays stable but the public ping spikes, the problem is more likely the modem, physical service line, or ISP network. A traceroute or PingPlotter session can also show where packet loss and latency begin.
Because you’ve tested multiple PCs, try isolating the network completely: connect one computer directly to the modem or gateway, temporarily disable other devices, and test with a continuous ping before and during a large download. If latency rises sharply only during downloads, bufferbloat or an overloaded connection is likely. If it spikes while the connection is otherwise idle, collect timestamped ping and traceroute results and give them to the ISP as evidence of an intermittent line or routing problem.
Don’t overlook the physical Ethernet setup. Try a known-good, undamaged cable connected directly to the router or gateway, and keep it away from power cables or sources of electrical interference. Also check Task Manager or your router’s traffic monitor during a spike for cloud backups, game launchers, torrents, operating-system updates, or another device saturating the upload. Heavy upload usage can cause bufferbloat and make gaming latency explode even when download speeds look normal.
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