Before you replace a single cable, read one number: the speed the PC and switch actually negotiated. It tells you whether you have a cable problem, a settings problem, or no problem at all.
When ping drops every few seconds, most people start swapping cables. Professionals read the negotiated link speed first. That is the speed both ends agreed on when the link came up, and on a healthy gigabit setup it reads 1.0 Gbps. A reading of 100 Mbps, or a reading that changes between visits, is the fault announcing itself - long before you spend money on parts.
Example only: the first adapter has fallen back to 100 Mbps on a gigabit network - a fault signature. The second shows the healthy 1 Gbps a gigabit link should report.
Get-NetAdapter | Select-Object Name, LinkSpeed - the fastest check on a server or a remote PCOn a managed switch, the port status page shows the same number from the other side. If the two ends disagree about the story, believe the mismatch itself - it is a clue.
1.0 Gbps, stable: the physical link is doing its job; if packets still drop, look at duplex agreement and switch port errors, not the cable category. 100 Mbps on gigabit hardware: the classic fallback - one cable pair damaged, or a forced Mbps setting like the one in the video case. 10 Mbps: something is very wrong or very old. Speed changes between checks: the link is renegotiating - every renegotiation is a burst of dropped packets, which is precisely the user complaint of an app reconnecting.
Link speed is a ceiling, not a measurement of your real transfer speed, and it says nothing directly about packet loss. A link can sit proudly at 1.0 Gbps and still drop packets if the duplex is mismatched. Read the link speed to classify the fault, then prove loss with a continuous ping count. Also note the reverse trap: a cheap old printer or camera that shows 100 Mbps may simply be a 100 Mbps device by design - check the device specification before condemning a cable.
See the video case - how one link speed reading and one adapter setting explained drops that survived a cable change.
Watch Full VideoOpen Settings, Network and Internet, Ethernet - the link speed is shown on the connection details. You can also use Task Manager, Performance tab, Ethernet, or run Get-NetAdapter in PowerShell and read the LinkSpeed column.
The link fell back. The usual causes are a damaged or badly terminated cable pair - gigabit needs all four pairs, 100 Mbps needs only two - or a forced Speed and Duplex setting on the adapter or switch port. Check the setting first, then test with a known-good patch lead.
Yes. Link speed only says what was negotiated. A duplex mismatch can run at full gigabit speed and still lose packets under load. Pair the speed check with a continuous ping test and, on a managed switch, the port error counters.