Question:

Why does the LinkIQ's cable test show a lower maximum speed than the switch test?

Answer:

When running a cable test you may observe the test result shows a different/lower maximum speed than the switch test even though the same link/channel was involved in both tests.

Switch Test:
 

Cable Test:

Switch Test:                                                            Cable Test:

This is a legitimate result

This is quite a common scenario, it can happen because during the very simple link negotiation the switch is only interrogated for the speeds it supports, and as long as all necessary wire pairs are present, the client (computer, storage, camera, etc.) may come to this wrong conclusion. During the operational phase it will then fall back to a lower speed or drop communication. This is one of many reasons why we want to use a LinkIQ, because it provides a simple and convenient way to find out for which speeds the cable is qualified.