Thunderbolt 4: Everything You Need To Know

It has been almost 10 years since the Thunderbolt hardware interface first showed up on a MacBook Pro thanks to Intel and Apple. Fast forward to July 2020, the fourth entry of the thunderbolt interface, Thunderbolt 4 was finally released.

However, from the surface Thunderbolt 4 may not seem so much different from its predecessor, Thunderbolt 3. Therefore, in this article, we will take an indepth look at the differences between the two protocols. Read on to find out.

Thunderbolt 4 Vs Thunderbolt 3

Thunderbolt 4 made its debut with Intel’s 11th Generation “Tiger Lake” Core processors. From Thunderbolt’s 4 first look it may seem that not much has changed when compared to its predecessor. For instance, both use the USB Type-C physical connector. Both offer a maximum throughput rate of 40Gbps. Lastly, both offer up to 100 watts of charging power.

What’s New In Thunderbolt 4?

When we take a closer look at Thunderbolt 4, various improvements give it an edge over Thunderbolt 3. For instance, it not only doubles the data but also the video requirements of Thunderbolt 3. Let’s find out what this actually means by exploring the specifications.

Thunderbolt 4 supports sending a video signal to one 8k display or two 4k displays. This is a significant improvement from its predecessor which only supports one 4k signal. The same goes for the PCIe data requirements. Whereby Thunderbolt 4 supports up to 32 Gbps data rate which is double Thunderbolt’s 3 16Gbps. This improvement is especially important for high-speed external PCIe devices like external graphics and storage which could see a significant increase in performance and speed.

Although we have USB-C extensions to maximize the length, we have still seen a significant improvement in the cable length with Thunderbolt 4 cables supporting 40 Gbps throughput at up to two meters in length. Which is a step up from the 0.5 meters Thunderbolt 3 cables.

Security Against Thunderspy

Unlike Thunderbolt 3, Thunderbolt 4 additionally offers better security over Thunderspy attacks. What is a Thunderspy attack? This is an attack whereby a hacker takes advantage of the vulnerabilities of a Thunderbolt port to steal your data. Even though the hacker needs physical access to your device for the attack to happen, it is deadly as it takes 5 minutes or less. And the attack can happen even when your device is locked, or hard drive encrypted.

How Does Thunderbolt 4 Prevent This?

Let’s first look at how the attacks occur to get a better idea of how Thunderbolt 4 protects your device. The PCI Express portion of Thunderbolt has Direct Memory Access. Basically, it bypasses the CPU to achieve faster access to the system memory. Thunderbolt 4 however prevents this by utilizing Intel’s Virtualization Technology which protects against attacks.

Using this technology, the Direct Memory Access is remapped to specifically isolate a portion of system memory for a connected device in such a way that the device cannot access other parts of the memory.

Although this type of attack is not a major concern for everyone, the protection offered by Thunderbolt 4 is essential for cooperate laptops which usually contain sensitive company information.

Intel Open Sourced Thunderbolt 3’s Specs

Back in 2019, Intel contributed their Thunderbolt protocol specification to the USB promoter group which meant that other chip makers would be able to build Thunderbolt-compatible silicon, royalty-free. One of Intel’s main aims with this plan is to drive mainstream adoption of Thunderbolt.

That being said, the convergence of USB and Thunderbolt protocols not only simplifies how people connect their devices but also increases compatibility among USB Type-C connector-based products.

Along with the release of Thunderbolt 3 specifications back in 2019, Intel also announced USB4 specifications which were formed based on Thunderbolt’s 3 specifications. Let us now take a closer look at USB4.

USB4 uses the same Type-C connector as Thunderbolt 3 the difference being that it neither needs Intel’s certification nor Intel’s Thunderbolt controller. As for the speed, USB4 devices can support two maximum speeds: 40Gbps and 20Gbps. For the end-user, this means that you need to carefully scan the device’s speed when buying a PC with USB4 to ensure you get exactly what you are looking for.

Thunderbolt 4 Vs USB4

Just like Thunderbolt 3, USB4 has many similarities with Thunderbolt 4 so it might be a little confusing. Apart from offering the same maximum bandwidth of 40Gbps, they both use the USB Type-C connector. Additionally, both Thunderbolt 4 and USB4 were introduced with  Intel’s 11th Generation “Tiger Lake” Core processors.

Thunderbolt 4 however is superior in terms of minimum data and video requirements. We already know that Thunderbolt 4 can run two 4k displays and transfer data up to 32Gbps. On the other hand, USB4 can handle running only one display and transfer data up to 16Gbps.

	Thunderbolt 4	Thunderbolt 3	USB4
1 universal port	✓	✓
40Gb/s cables up to 2 meters	✓
Accessories with up to 4 TB ports	✓
Min PC speed requirement	40Gb/s	40Gb/s	20Gb/s (40Gb/s is optional)
Min PC video requirement	2 x 4K displays or 1 x 8K display	1 x 4K display	1 display (no min resolution)
Min PC data requirements	PCIe 32Gb/s USB 3.2 10Gb/s	PCIe 16Gb/s USB 3.2 10Gb/s	USB 3.2 10Gb/s
PC charging port required	At least one
PC wake from sleep w/TB dock connected	Required
Min PC port power for accessories	15W	15W	7.5W
Thunderbolt networking	✓	✓
Mandatory certification for PCs and accessories	✓	✓
Intel VT-d based DMA protection required	✓
USB4 specification	Compliant	Compatible	Compliant

Summing Up

USB4 is a capable connection, additionally, it’s fast. However, because it does not require certification and further allows production in variation it is difficult for consumers to match their devices with computers.

Thunderbolt 4 on the other hand looks like the best choice both on paper and practically. It is not only superior in terms of speed and data requirements to USB4 but also has an edge over Thunderbolt 3.

Want to read more articles like this? Subscribe to our blog and be the first one to learn about new tech trends.