Introduction

With AMD's Socket AM5 platform around the corner, there has been some renewed interest in USB4, as things had been pretty quiet up until the ASMedia ASM4242 controller announcement last month, just ahead of Computex. As such, we thought it was a good time to put together an extensive look at what's happening in the USB space, what USB version 4 offers, and how it compares to solutions like Thunderbolt. Technically, Intel was the first company to launch a USB4-compatible host controller with their "Maple Ridge" Thunderbolt 4 controller, also known as "JHL8340" (single-port) and "JHL8540" (dual-port). For some reason, Intel isn't marketing any of its Thunderbolt 4 products as "USB4 compatible" despite the fact that they appear to be certified.



That said, it was reported almost a year ago that the USB PD controllers from TI Intel has certified for use with its Thunderbolt 4 controllers aren't USB4 certified (Igorslab). This means the whole solution can't be marketed as "USB4 compliant" despite being "USB4 compatible." That's why Intel asked its partners not to certify their Thunderbolt 4 devices for USB4, as they wouldn't pass the certification. It's unclear when this will change.

Intel's discrete Thunderbolt 4 controllers aren't listed in the public USB Implementers Forum database of certified devices even though a pair of its mobile SoCs with native Thunderbolt 4 support are. The database contains around 300 certified USB4 items already, ranging from the aforementioned Intel CPUs to connectors and e-marker chips, a surprisingly large amount of cables, and a few other things. The ASMedia ASM4242 is not yet one of the certified devices, and although that was what was being communicated, it seems to have been misunderstood by the Taiwanese media that were the first to report on the matter. On the other hand, AMD's mobile Ryzen 6000-series CPUs have passed certification, but are not listed in the public database, either, so it might just be some time lag between database updates.

It's unlikely that we'll see anyone outside of Intel and ASMedia producing another discrete USB4 host controller, largely due to lack of demand, but also based on the engineering requirements. That said, at some point in time, it's likely that we'll see various ARM based processors implementing USB4 support. As for Apple, it's unclear if their Thunderbolt 4 implementation will get certified for USB4, but this might, as in the case of Intel, not mean much as Apple's controllers are compatible with USB4. As to AMD's implementation, we don't know much about it either, but more information should hopefully appear as notebooks based on the Ryzen 6000-series start to arrive in the retail market.

That's the current state of USB4 in the market; next we're going to take a closer look at some of the advancements and improvements USB4 brings to the table, and try to clear up some of the confusion that seems to be going around. Some of it is thanks to the rather poor communication by the USB-IF itself, at least when it comes to providing clear information to consumers, as the USB-IF seems to cater largely to its members.