How to troubleshoot Intel® Ethernet Adapters Gigabit speed issues?

Using devices that seem to be capped at either 10/100mbps instead of the full Gigabit speed.

Troubleshooting:

1. Check current driver version.
   1. Update latest one 
2. Check that auto-negotiation is enabled on both sides:
   1. Device manager within Windows > check properties of the adapter
      1. Gigabit recommended setting is Auto-negotiation.
3. Make sure your Model/Access-point/Switch or device on the other side comes with full Gigabit support.
4. Make sure that a CAT-6 cable or superior is being used.
   1. This is required for reliable Gigabit speed. Consider swapping the cable with one that is known to be working.
5. Try a point-to-point connection between the adapter and another computer:
   1. Transfer a file and measure its results to make sure that it meets the Gigabit speed.
   2. For instructions about this, contact your operating system support.

After you do these troubleshooting steps, if the issue persists, make sure your local ISP set up the correct requirements for a full Gigabit connection. If this is the case, proceed with replacing the adapter.

Drivers could be the most likely cause of this issue. Sometimes cabling, such as cat-5, isn't sufficient to perform Gigabit speed.