WhatCable Turns Apple Silicon Macs Into Free USB-C Testers, Exposing 100W and 10Gbps Limits
Updated
Updated · The Verge · Jul 13
WhatCable Turns Apple Silicon Macs Into Free USB-C Testers, Exposing 100W and 10Gbps Limits
3 articles · Updated · The Verge · Jul 13
Summary
WhatCable uses Apple Silicon Macs’ existing USB Power Delivery and IOKit data to show a cable’s claimed speed, power rating, live voltage and current, and the actual negotiated link.
Apple’s public APIs let the free menu-bar app read e-marker details and port-controller data without root access, surfacing information macOS collects but does not normally display.
Tests in the report showed why that matters: one cable correctly delivered 100W but only 480Mbps, another 10Gbps/100W cable had degraded in real use, and a supposed 10Gbps charging cable fell back to USB 2.0.
Creator Darryl Morley says the core Mac app will stay free, while a £9.99 Pro tier adds real-time power monitoring, diagnostics, and a terminal view.
Morley has also released a simpler Mac utility called WhatPort and is exploring Linux, but says Windows, Android, and iOS lack the low-level access WhatCable needs.