Differences Between Thunderbolt 4 and USB4

September 15, 2020

Differences Between Thunderbolt 4 and USB4

Image via xda-developers.com

Thunderbolt 4 and USB4 are the next technologies to battle it out for the best connectivity standard. Both technologies are capable of 40Gbps speeds, have a Type-C connector, and support power and video passthrough, but there are some differences.

In this article, we will explain how Thunderbolt 4 and USB4 are similar and what sets them apart. Unlike USB-C and Thunderbolt 3, Tb4 and USB4 are very similar in many ways, and it may be hard to differentiate them, even for the tech-savvy.

USB technology is the oldest technology, available in most computers and peripherals. Over the years, it has evolved from slower USB 1.0 to provide impressive 20Gbps speed with the latest USB 3.2 standard. However, USB still lags behind Intel's Thunderbolt 3 technology, which offers higher bandwidth of up to 40Gbps.

However, things are about to break even after Intel contributed the Thunderbolt 3 specification to the USB Implementers Forum (USB-IF) to form the next generation USB4 standard. USB4 will have the same speeds as Thunderbolt 3, topping at 40Gbps and capable of driving dual 4K displays and 100W power delivery. But there is a catch. Most of the USB4 features are optional, meaning manufactures are free to choose which ones to support.

Thunderbolt 4, on the other hand, is the next-generation standard of Thunderbolt connectivity standard. Intel announced Thunderbolt 4 at CES 2020, with the first devices expected to ship later this year. Thunderbolt 4 won't be faster than USB4, but it will be better.

Minimum Requirements: The Real Difference

We expect USB4 to become mainstream quickly than Thunderbolt 4 because of the fewer implementation costs.

Manufacturers don't need certification or testing from Intel to implement USB4. Besides, USB has low minimum requirements compared to Thunderbolt 4. Plus, backward compatibility with older USB standards will resurrect those ever-so-useful USB hubs.

Intel requires USB4 devices to support 20Gbps speeds, single 4K display, and 7.5W power output. That means while USB4 is capable of 40Gbps link speeds, manufactures can choose to offer 20Gbps rates to minimize costs. The same applies to Thunderbolt 3. There are plenty of Thunderbolt 3 cables in the market that maxes at 20Gbps link speeds.

Therefore, one must be careful when buying future USB4 products. You can check the product description or review sites to ensure every feature you pay for is supported.

Intel developed Thunderbolt 4 at the right time to clear the confusion created by Thunderbolt 3 and USB4. All Thunderbolt 4 devices must support 40Gbps and drive dual 4K displays or a single 8K display. But wait, that's actually USB4 at its highest settings. Thunderbolt 4 has double the minimum requirements as USB4, which is the highest possible specs supported by the two technologies.

Manufacturers can no longer cut costs when implementing Thunderbolt 4, ensuring devices deliver reliable connection and performance. That is the main difference compared to USB4. Now you don't have to double-check the device specifications as all certified Tb4 devices must meet the highest possible bandwidth of 40Gbps.

 

Thunderbolt 4

USB4

One computer port

Yes

No

Universal 40Gbps cables up to meters in length

Yes

No

Accessories with four Thunderbolt ports

Yes

No

Minimum speed requirements

40Gbps

20Gbps

Minimum PC video requirements

Two 4K displays

One display (No Minimum)

Minimum PC data requirements

PCIe 16Gbps

USB 3.2 – 10Gbps

USB 3.2 – 10Gbps

Required PC charging on at least one computer port

Yes

No

Required PC wake from sleep

Yes

No

Minimum PC port power for accessories

15W

7.5W

Thunderbolt networking

Yes

No

Mandatory certification

Yes

No

Cable testing and cable quality audits

Yes

No

Required Intel VT-d based DMA protection

Yes

No

via Intel

Thunderbolt 4 Raises the Bar with New Features

Besides the strict minimum specs, Thunderbolt 4 brings other outstanding features not available on USB4. The next-gen docking station will feature a much smaller footprint while providing up to four Thunderbolt 4 ports. The new docks will also allow you to wake your computer from sleep by tapping a keyboard or mouse connected to the dock.

Thunderbolt 4 pushes for a truly universal port by requiring PC to include at least one port for charging. That contrasts with Thunderbolt 3 and USB4 as some laptops have Thunderbolt 3 ports with no charging capabilities. The minimum power delivery on Thunderbolt 4 is 15W, which is higher than USB4.

The last critical feature of Thunderbolt 4 is protection from Direct Memory Attacks (DMA). DMA ports like Thunderbolt and USB4 provides direct memory access to peripheral devices to ensure high-speed performance. Thunderbolt 4 requires Intel Virtualization Technology for Directed I/O (VT-d) to prevent physical DMA attacks by creating virtual memory for each connected device to block access to system-wide memory.

What About the Cables?

The USB-IF finally sorts out the weird naming schemes of their USB standards. Since the new USB4 can support either 20Gbps or 40Gbps speeds, the new cables will now include the supported bandwidth in the logo. The same applies to the last USB standards that support 5Gbps, 10Gbps, and 20Gbps. It's now easy to identify the supported speeds by looking at the cable.

 

Image via USB-IF

 

On the other hand, Thunderbolt 4 cables include the Tb4 logo to distinguish them from thunderbolt 3. Thunderbolt 4 cables have the edge over USB4 as they support 40Gbps speeds over 2 meters. USB4 supports 40Gbps within one meter with the bandwidth reducing to 20Gbps on 2 meters or longer cables. Thunderbolt 4 will be backward compatible with Thunderbolt 3 devices and cables.

USB 4 and Thunderbolt 4 availability

PCs with 11th generation "Tiger Lake" processors will be the first to integrate Thunderbolt 4. Both Thunderbolt 4 and USB4 devices will be available later this year. ASUS and Lenovo recently announced their latest ZenBook and Yoga laptops will feature 11th gen Intel processors with Thunderbolt 4 connection.

Bottom Line

Thunderbolt 4 and USB4 have the same specs, but Thunderbolt 4 is more reliable with tighter minimum specs. Both can drive dual 4K displays, transfers data at 40Gbps, and provide power to charge a laptop. But USB4 has lower minimum specs, and makers can choose not to implement all the features to minimize costs.

If you're looking for the best USB4 or Thunderbolt 4 performance, choose Thunderbolt 4. Thunderbolt 4 demands all manufacturers meet the highest possible requirements with no compromises, leading to reliable performance. With Thunderbolt now royalty-free, many devices will feature Thunderbolt 4 in the future.

However, it doesn't mean you shouldn't get USB4. You can still get USB4 devices with the best features like 40Gbps; ensure to confirm the specs before buying. Besides, USB4 is backward compatible, so don't throw your old USB hubs yet.




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