USB-C ports have become the standard connection on contemporary Windows laptops, yet not all ports deliver the same performance. The USB-C standard encompasses various specifications, with USB4 being the latest iteration. Within USB4, there are distinct performance tiers that add another layer of complexity to the user experience.
According to a recent blog post by Microsoft’s Senior Product Manager, Ugan S., a notable 27% of Windows PCs equipped with USB4 ports have encountered a frustrating “limited functionality” notification. This alert typically arises when users attempt to connect peripherals, particularly displays, that the USB-C port cannot adequately support.
The underlying issue stems from the inconsistent implementation of USB-C across different laptop manufacturers. Many brands incorporate USB-C ports without providing comprehensive details about their capabilities, leaving users in the dark regarding what to expect. Microsoft illustrates this common scenario:
“Five minutes before a customer demo, I plug my 4K monitor into the USB-C port on a brand-new laptop. The display doesn’t light up, and now I’m scratching my head — the cable fit, so why isn’t it working?”
To address these challenges, Microsoft is introducing an updated Windows 11 Hardware Compatibility Program (WHCP). This initiative will ensure that laptops shipping with Windows 11 version 24H2 will carry WHCP certification. Microsoft promises two significant assurances regarding USB-C functionality:
- Universal USB data, charging, and display support across all USB-C ports. Users can expect older USB peripherals to function seamlessly.
- Full compatibility for USB4 ports with 40Gbps performance with Thunderbolt 3 and USB4 peripherals. This means any USB4 or Thunderbolt 3 device will work reliably on every port.
These commitments come with specific minimum capabilities for each USB-C version, clearly outlined in a table shared by Microsoft. The enforcement of these standards through WHCP will yield several benefits for users.
Most notably, users can trust that their USB devices will function without issues, thanks to the requirement for USB-IF certified silicon in certified laptops. Each USB-C port on these devices will now include USB Power Delivery capabilities, eliminating inconsistencies in charging capabilities. Additionally, external display support will be standardized, as DisplayPort Alt Mode will be mandatory for all USB-C ports, ensuring users can connect screens without complications.
Furthermore, a new requirement for Microsoft’s driver stack guarantees that PCs will receive the latest USB driver updates, enhancing overall performance.
What about USB4’s 40Gbps and 80Gbps standards?
USB4, the latest iteration utilizing the USB-C connector, introduces further complexity with its two performance tiers: 40Gbps and 80Gbps. Until recently, these tiers were not distinctly marketed, leading to confusion due to their significant differences in capabilities.
The USB Implementers Forum (USB-IF) has introduced guidelines for separately identifying USB4 performance tiers, but Microsoft is taking additional steps. New Windows laptops featuring USB4 connections at 40Gbps will now be required to ensure full compatibility with both USB4 and Thunderbolt 3 accessories. If a laptop advertises a USB port with 40Gbps performance, users can expect it to maintain that speed consistently.
Moreover, WHCP certification will extend to 80Gbps USB4 ports, mandating that they provide 80Gbps transfer speeds in both directions, along with an asymmetric 120Gbps / 40Gbps mode designed specifically for high-resolution external displays. This positions it alongside Thunderbolt 5, Intel’s branded version of USB4 v2.
The new WHCP certification for USB-C connectivity will be applicable only to new laptops that ship with Windows 11 version 24H2. This certification will be enforced through a Hardware Lab Kit, which incorporates user feedback, telemetry, automated testing, and validation led by original equipment manufacturers (OEMs). As Windows 11 evolves, this program is expected to receive updates with each major release.
