Mac App Flags USB-C Cables That Overstate 240W and 40Gbps Specs
Updated
Updated · ZDNet · Jul 15
Mac App Flags USB-C Cables That Overstate 240W and 40Gbps Specs
1 articles · Updated · ZDNet · Jul 15
Summary
Testing with WhatCable on an Apple Silicon Mac, ZDNET found several USB-C cables did not match their advertised capabilities, including one that claimed 240W but never exceeded 100W.
WhatCable reads a cable’s actual USB-C specs directly on Macs running macOS 14 or later, helping explain slow charging, weak data speeds or flaky dock connections without separate hardware.
The free app can identify cables even when unplugged from devices, while a £9.99 pro tier adds 16 features including protocol diagnostics, display diagnostics and a live power meter.
The author said some app functions were unreliable, but still used it to spot damaged or defective cables and recycle underperforming ones.
The test underscores a broader USB-C problem: visually identical cables can vary sharply, from basic charge-only cords to models marketed for 100W or 40Gbps performance.