Thunderbolt 4 vs Thunderbolt 3 | What Makes Thunderbolt 4 Special?

Whenever you invest in a laptop or a PC, you look up the specification sheets to determine the number and types of connectivity ports offered along with the device.

You will find the USB and HDMI ports to connect to your compatible devices among the various options available.

Today, the latest generation of laptops and desktops come with advanced ports like Thunderbolt 3, USB4, and Thunderbolt 4.

These advancements in technologies come with their advantages. We shall discuss the concept and design of these ports and understand how they are different from each other.

If you have used a MacBook or recently switched over to the high-end Windows notebooks with the latest 10th or 11th generation Intel Core chips, you would have come across these terminologies.

Are you left scratching your heads about what these ports can do because they seem so similar to the USB Type-C connectivity ports?

Besides allowing data transfers at speeds beyond what the standard USBs deliver, these connectivity ports can do a host of other activities.

Thunderbolt – A peek into the history

Before we discuss the capabilities of Thunderbolt 4 and understand how it is different from Thunderbolt 3 and USB4, let us explain what Thunderbolt is.

Thunderbolt made its initial appearance in 2011 in an Apple MacBook Pro.

The Thunderbolt port, introduced by Intel and Apple, was similar to the mini-DisplayPort connector but with a ‘lightning’ symbol to distinguish it from the others.

It combined two technologies, DisplayPort and PCI Express, in a single cable to enable high-resolution displays and high-speed data transfers with speeds up to 10Gbps.

Thunderbolt 2 was an improvement over the initial Thunderbolt technology, as it doubled the bandwidth to 20Gbps. Besides, it supported DisplayPort 1.2, thereby driving the video signal to a 4K display.

Thunderbolt 3 improved the data transfer speed to 40Gbps. Secondly, it dispensed with the mini-DisplayPort connector and changed to the USB Type-C port.

Another addition was the USB PD (Power Delivery) feature up to 100 watts of power. This feature enabled the laptop/PC to charge your smartphone or another laptop over the port.

Thunderbolt networking with 10Gbps was another additional that provided sufficient video bandwidth that led to an array of applications ranging from single-cable docks to charging different devices like external GPUs and supercharging a laptop’s graphics capabilities.

Intel developed the technology further to introduce Thunderbolt 4 in 2020, with the 11th generation Tiger Lake processors supporting this technology. Simultaneously, these Tiger Lake processors ushered in USB4 technology to add to the confusion.

Overview of the differences between these different ports

This table should explain the distinction between USB 3, USB4, Thunderbolt 3, and Thunderbolt 4.

ParametersUSB 3 – DisplayPort TechnologyUSB4Thunderbolt 3Thunderbolt 4
Universal PortNoNoYesYes
Data Transfer speeds 40GBps cables up to two metersNoNoNoYes
Accessories with up to 4TB portsNoNoNoYes
Minimum PC/laptop speed requirement10Gbps20Gbps (optional – 40Gbps)40Gbps40Gbps
Minimum PC/laptop video requirementOne display with no minimum resolutionOne display with no minimum resolutionOne 4K displayTwo 4K displays or one 8K display
Minimum PC/laptop data requirementUSB 3.2 5GbpsUSB 3.2 10GbpsPCIe 16Gbps, USB 3.2 10GbpsPCIe 32Gbps, USB 3.2 10Gbps
Laptop charging portNoNoNoOne required
PC Wake up from sleep with TB dock connectedNoNoNoNecessary
Minimum PC/laptop port power for accessories4.5W7.5W15W15W
Thunderbolt NetworkingNoNoYesYes
Mandatory Certification for PCs and accessoriesNoNoYesYes
Intel VT-d based DMA protection necessaryNoNoNoYes
USB4 specificationCompatibleCompliantCompatibleCompliant

How is Thunderbolt 4 different from Thunderbolt 3?

For an Apple MacBook user, there is not much of a difference between Thunderbolt 3 and Thunderbolt 4. Thunderbolt 4 displays backward compatibility with Thunderbolt 3.

If you look at the MacBook specifications, Apple lists it as Thunderbolt/USB4, including Thunderbolt 3.

However, Windows PC/laptop users will notice the difference straight away because the Thunderbolt 3 version available in most Windows appliances has limited features. Apple provides all Thunderbolt 3 features in its MacBook series.

Though a Windows PC running on the 10th generation Intel Core CPU (the higher end) supports Thunderbolt 3, it could lack the full 40Gbps bandwidth. All laptops/PCs might not support multiple displays or power delivery. Thunderbolt 4 changes the scenario entirely by making available the same features that Apple users get.

As Thunderbolt 4 requires a mandatory certification for all PCs, it standardizes Thunderbolt 3 for everyone. While being backward compatible, Thunderbolt 4 devices are also ready for future expansions or technological advancements.

The 11th generation Intel Core CPUs (the higher end) come with Thunderbolt 4 certification to join in the fun without limitations.

For receiving Thunderbolt 4 certification, the respective devices should satisfy the following four minimum requirements.

  • Have a minimum of one TB4 port for charging the computer
  • Thunderbolt 4 docking stations have to support wake-from-sleep on touching the mouse or keyboard of the connected computer/laptop.
  • Protection from Direct Memory Access (DMA) attacks is necessary.
  • The minimum video and data transfer speed requirements for TB4 should be double those for TB3.

Let us compare and see how Thunderbolt 4 is better than Thunderbolt 3.

The Apple MacBooks working with the indigenous Apple M1 chip are compatible with Thunderbolt 3. However, they have a limitation because they cannot run more than one external display natively. Thunderbolt 3 supports one external 4K monitor display, whereas Thunderbolt 4 supports two 4K or one 8K display.

Thunderbolt 4 allows you to wake up your laptop/PC with one shake of the mouse or a tap on the keyboard. Thunderbolt 3 does not offer this facility.

Compared to Thunderbolt 3, Thunderbolt 4 technology offers additional data safety because it requires Intel VT-d-based DMA protection, also referred to as DMA remapping. We shall discuss this aspect a bit more in detail in one of the forthcoming paragraphs (Protection from Thunderspy Attacks).

Thunderbolt 4 requires PCIe at 32Gbps for storage speeds up to 3000Mbps. It is twice the requirement of Thunderbolt 3 ports (16Gbps). Some Apple MacBooks models offered this facility, whereas some had less bandwidth available on the RHS (right-hand-side) Thunderbolt ports.

With Thunderbolt 4, you get four lanes of PCI Express available, whereby PCIe can consume up to 32Gbps of the total 40Gbps available Thunderbolt bandwidth. It is an improvement over Thunderbolt 3, where some laptop manufacturers offered 16Gbps of PCIe bandwidth.

Thunderbolt 4 has an advantage over Thunderbolt 3 because they include hubs and docks with multiple Thunderbolt ports. Besides, the data transfer cables can be up to two meters long and still handle 40Gbps bandwidth. In Thunderbolt 3, the wires could have a maximum length of 0.7 meters to handle full bandwidth.

What makes Thunderbolt 4 special?

We have discussed the differences between Thunderbolt 3 and Thunderbolt 4 in the above paragraphs. Besides, these distinctive features. Thunderbolt offers unique facilities that make it special.

Thunderbolt Hubbing

Thunderbolt is not something new for MacBook users. The latest Thunderbolt 4 technology is a kind of software update for them. However, MacBook users will need Apple’s latest operating system, Big Sur, to take advantage of Thunderbolt 4’s new Hubbing software.

This facility eliminates the risks of Thunderbolt device daisy-chaining. Daisy-chaining feature enabled users to connect multiple Thunderbolt devices in a long chain. However, removing any one device in the chain, except the last one, resulted in the others becoming unusable until you re-establish the chain.

Thunderbolt Hubbing allows you to have four Thunderbolt ports in a hub, each independent of the others. Thus, disconnecting any one of the devices does not affect the other connected appliances. This facility is due for introduction in 2021.

Protection from Thunderspy Attacks

In a Thunderspy attack, the malicious actor can steal data by exposing the vulnerabilities of a Thunderbolt port. However, such attacks require physical access to your PC/laptop. While it takes around five minutes for the attack, it is effective even when the computer is in sleep/lock mode or your HDD is encrypted.

The Thunderspy attack takes advantage of the PCIe portion of your Thunderbolt port and its Direct Memory Access to bypass the CPU and access system memory. Thunderbolt 4 protects against such DMA attacks because it requires Intel’s Virtualization Technology for Directed I/O (Intel’s VT-d-based DMA protection).

Intel’s VT-d offers DMA remapping, a process that isolates a portion of your system memory for the connected device. Thus, the device cannot read/write to other areas of your memory. As it fortifies a specific portion of your system memory for the Thunderbolt device, it cannot access other places to overwrite data, such as your device’s password protection.

At this juncture, let us clarify that the Thunderspy threat is remote for standard users. It is a significant concern for corporate users who travel a lot, get misplaced in unsecured locations, or contain sensitive financial and business data.

Thunderbolt 4 Vs. USB4 – The differences

Intel introduces new technology, USB4, in its Tiger Lake Core processors, the 11th generation CPUs. While it is also simultaneously introducing Thunderbolt 4, there can be confusion because both these technologies use a similar connectivity port, the USB Type-C connector.

You can connect a USB device to your Thunderbolt 4 port. However, the connection will default to USB4 speeds. The standard data transfer speed of USB4 is 20Gbps. Yes, you have a 40Gbps option with a USB4 connection, as well.

USB4 differs from Thunderbolt 4 as it can run a single 4K display at 16Gbps, unlike the dual 4K display at 32Gbps offered by Thunderbolt 4. Besides, USB4 does not offer the wake-from-sleep feature that Thunderbolt 4 is renowned for. It also does not provide 10Gbps networking.

However, USB4 has one advantage over Thunderbolt 4. The logos are more informative.

The connectivity ports have USB 20Gbps and USB 40Gbps adjacent to the USB Type-C ports to indicate which speed you are using.

The Intel PC/laptop does not provide such information with its Thunderbolt logos. All you have is the ‘lightning’ symbol. Therefore, you cannot distinguish whether it is a Thunderbolt 3 or Thunderbolt 4 connection. Some cables come with the numeral 4 written next to the logo to indicate it is a Thunderbolt 4 cable.

Thunderbolt 4 Introduction – Redefining Computing

The latest 11th generation Intel Tiger Lake CPUs offer Thunderbolt 4 connectivity on some of the high-end processors. Though all 11th gen CPUs feature USB Type-C connectivity, it is better to check the specifications to verify whether it is Thunderbolt 4 compliant. Otherwise, it might offer Thunderbolt 3 capabilities.

The latest Apple MacBooks also feature USB4 ports, but the models released by 2020-end do not have Thunderbolt 4. They feature Thunderbolt 3 connectivity. With the release of Apple’s M1 silicon chip, one has to wait and see whether Thunderbolt 4 is available on the MacBook Pro, Air, and Mini models.

Thunderbolt 4 technology can redefine computing as it comes with a host of exciting features to distinguish it from Thunderbolt 3. Thunderbolt 4 is here to stay until the introduction of the next technological advancement.

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