My wired internet connection is mostly steady, but it randomly drops to 0 Mbps for a second or two, creating a sharp dip before immediately recovering. Sometimes this happens repeatedly, while other times several minutes pass between interruptions. The result is brief freezes in livestreams and noticeable lag or full stops while playing online games.
I use Xfinity service advertised around 1 Gbps and previously had no issues with streaming or gaming. The problem began suddenly after I returned home from being away for a few days. I replaced the modem, router, RG-6 coaxial cable, and Ethernet cable, partly because I noticed possible tooth marks from my cats, but the issue continued. I also performed a clean Windows installation, which seemed to help temporarily. Malware scans and cleanup have not found anything suspicious.
What would be the best way to determine whether this is caused by my computer, Ethernet hardware, modem signal, router, or the ISP connection?
3 Answers
Since replacing the modem and cables did not help, check the modem’s diagnostic or signal page if it is available. Look for events such as timeouts, ranging failures, or signal levels outside the recommended range. If the diagnostics are inaccessible, ask the ISP to check the line and connection history rather than only running a basic speed test; short interruptions can be missed by a speed test.
The Task Manager graph only shows the transfer rate, so a drop to zero does not necessarily mean the link itself disconnected. Use continuous ping tests while the problem occurs—for example, ping your router’s local address and a reliable internet address at the same time. If both fail, check the PC, Ethernet link, or router. If the router responds but the internet ping fails, the issue is more likely the modem or ISP.
Test the connection from another computer or device first. If multiple devices experience the same brief freezes, the problem is probably outside your PC and you should contact the ISP. If it only happens on this computer, focus on the Ethernet adapter, its driver, power-management settings, or the motherboard’s network hardware.
I tried checking the modem’s usual diagnostic address, but it appears to be blocked. I’ll test another device and collect ping results so I can give the ISP more useful information.