WhatCable Pro is a deep USB-C diagnostics tool designed specifically for Apple Silicon Macs running macOS 14+. While the free version identifies basic cable capabilities, the Pro tier offers advanced, real-time troubleshooting directly from IOKit data—requiring no extra software or root access.

Key Features

• Negotiation Diagnostics: Easily spot bottlenecks by comparing what your Mac port, cable, and connected device support side-by-side.
• Live Power Metering: Displays real-time wattage, voltage, and amperage per port, updating every 2 seconds.
• Hardware & Port Health: Tracks lifetime port errors, resets, and monitors liquid detection (LDCM) sensors.
• Advanced Insights: Offers Power Delivery (PD) contract inspection, cable resistance estimation, and DisplayPort Alt Mode lane mapping.
• Developer Friendly: Includes a CLI monitor mode (whatcable –monitor) and desktop widgets for quick tracking.

What's New:

Version 0.13.4

• CIO bottleneck analysis now covers TB3 (20 Gbps). Previously only TB4 and TB5 speeds were mapped. If the Thunderbolt controller reports a TB3-class cable, the bottleneck diagnostic handles it correctly instead of falling back to "unknown."
• Power Monitor shows a spinner while waiting for telemetry. Bus-powered USB devices (external drives, etc.) can take 30-60 seconds before macOS starts reporting power data. Previously the Power Monitor showed a static "No power data" message during that window, which looked like nothing would ever appear. Now it shows a spinner so you know data is on the way.
• All watchers refresh on plug/unplug events. Power, PD identity, USB3, and TRM data previously only re-read on manual refresh. If IOKit properties lagged behind service registration, the popover could show stale data for a while. Now all watchers refresh together during the plug/unplug burst and the background poll.

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