Cable connectivity is a popular way to connect to the Internet and, as of 2010, is generally considered to be the fastest of all the different methods (DSL and dial-up). While most users experience a problem-free relationship with cable connectivity, sometimes there are issues that slow Internet speed. Using common sense and looking at all the different areas suspected of bogging things down is the best way to troubleshoot a less-than-zippy cable connection. Make sure you consider everything, and don't rush to judgment.
Things You'll Need:
Coaxial cable splitters
Ethernet RJ-45 cable
Instructions
Narrow the scope of the problem. Find out if it's limited to one computer or every computer on the network. If you have only one computer connected, borrow a laptop and attach it to the same network connection to see if the problem lies in the overall connection or with the computer itself. Disable any firewall or other security settings on your computer to see if that solves the problem.
Reboot your cable modem, router and computer, in that order. Allow at least 45 seconds for each component to power on before rebooting the next one. If things are still slow, check with a neighbor to see if the problem is widespread or if it's limited to your connection.
Unplug your router and connect your computer directly to your cable modem. If the speed increases, the problem lies in the router or with one of the connections between the computer and the modem. Replace cables to see if that solves the problem.
Check all of the cable connections in your building, starting at the point of entry, and tighten all junctions in the line all the way to your cable modem. Look for any frayed or damaged wiring, and make sure that no exposed metal surfaces are touching any pipes, conduits or electrical boxes. Replace any inexpensive splitters that diminish the signal. Similarly, avoid having too many splitters and spliced connections.
Contact your cable company if all of your efforts to solve this issue fail. If the problem is consistent, try to pinpoint a time when things changed (an electrical storm, construction that might've compromised the signal, etc.). If the problem is intermittent, see if there's any pattern to the loss of speed. Items as diverse as rain (water on exposed wires has been known to cause interference), outsiders piggybacking on your cable connection or generally high Internet traffic can diminish your cable speed.
Tips & Warnings
Swapping your modem for a newer model sometimes helps.
Use an impartial third-party site for a speed test, not one controlled by your ISP.
Upgrade to the latest version of your web browser.
Your cable company may charge you for a service visit if they have to troubleshoot the issue in person.
Expect to spend quite a bit of time on the phone if you decide to contact your cable company.
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