Case 1: The client just upgrades their ISP and most computers accessing Internet speed over 500 Mbps except one PC. After checking the Ethernet card, we find it is old and speed limit to 100 MB.
Case 2: When test computer speed, one of computers is slow than others. Replacing the able with cat5e cable fixes the problem.
Case 3: The client reports that their computers keep having slow or dropping problem randomly. We fixed the problem by update Cisco Switch firmware.
Case 4: We have tried above troubleshooting, but can’t fix the problem even after restarting the computer. Finally, we find the user s uploading 20GB files to OneDrive. Pausing the OneDrive sync fixes the problem.