USB4 is on the road and has just been presented at
the CES. While USB3.1 Gen2 is limited to 10Gbps,
USB4 starts at 20Gbps and will also have 40Gbps.
Thunderbolt 4 will be USB4 but with all features.

While USB4 may exclude some non-necessary features to keep costs low, Thunderbolt 4 has to include all features USB4 can provide. This will make Thunderbolt 4 devices significantly more expensive as the controller chip will be also more complex to be built.

But back to USB4: While USB3.1 Gen2 has been limited to 10gbps and thus might become the bottleneck of devices that can easily bypass the 1.25GBps speed barrier (for example NVMe SSDs in a USB3.1 Gen2 housing that can achieve up to 5GBps normally) USB4 might provide enough speed even with these fast SSDs inside. But not only single-end devices might benefit from a quadrupled speed. Also USB4-capable hubs and docking stations might be able to handle fast-speed devices more reliably.

Of course the speed demand has already hit USB3 with the quite rare USB3.2 standard which is only used by one ASMedia chip and capable to provide 20Gbps (2.5GBps). But even then modern SSD drives connected via USB3.2 may face interface limitations. With 40Gbps there’s a theoretical 5GBps speed available which can only be hit by the most recent PCIe4 M.2 NVMe SSDs today that achieve up to 6GBps and thus would need 48Gbps bandwidth. But let’s not pick on USB4 already. The new standard isn’t primarily designed for High-end storage devices that even fully fill the 40Gbps. The main goal is to provide a superfast bus for common applications such as image and sound transport and casual data exchange or simplified network connection using a USB4 dongle that provides an Ethernet port. With this in mind, even a full 10GbE port can be implemented without the need of a separate network chip.

But as we know, this all would require enough PCIe lanes these chips can communicate with the CPU on. For now, AMDs new TRX40 chipset provides up to 72 PCIe4.0 lanes and another 18 come from recent Threadripper processors which add up to 90 PCIe lanes in total. This shows that even the most demanding computer setup will have sufficient bandwidth on an AMD-based system.

The Intel Z490 chipset however only provides up to 40 PCIe lanes Gen3.0 which split up to 24 provided by the chipset and 16 provided by the CPU, if it is an Intel Comet Lake processor (10th Gen)). So Intel might have to find a way to increase bandwidth with their upcoming chipsets in order to be able to compete with AMD here.

Back to USB4 and Thunderbolt 4 again:

Of course the USB IF consortium has already presented the upcoming logo lineup to help customers identify what is USB4 capable:

While USB4 will definitely be a speed boost, Thunderbolt 3 already provides 40Gbps and thus won’t benefit from a speed update as Thunderbolt 4 will also “only” provide 40Gbps.

Intel seems to plan an implementation of USB4/Thunderbolt 4 with their upcoming CPU lineup (Tiger Lake) which will be the 11th generation of the Core-i(x) series. Despite of that, companies of external devices will definitely start producing devices with USB4/Thunderbolt 4 in advance as AMD will soon support these most likely by releasing PCIe Add-on cards. There’s no reliable information on the upcoming X570 chipset if it already contains USB4 / Thunderbolt 4 support natively and thus making Add-on cards obsolete.

Anyway… we love the way things evolve right now and we can only hope that Intel has finally heard the wakeup call and starts designing comparable chipsets/CPUs at fair prices. If they keep staying in hibernation, they might totally losse connection. Another thing is that NVidia might also try to find another alliance partner as their graphics cards might soon fully load the PCIe bus. And NVidia already fears loosing ground to AMD according to AMDs recent NAVI announcements.