In the past, you needed Thunderbolt if you wanted to connect an external GPU to your laptop, but things have changed now that USB4 has been introduced. Since USB4, Thunderbolt 3, and Thunderbolt 4 all have the same connectors and similar specifications, differentiating between the three can be tricky. This article covers the differences between these connection interfaces and covers whether you can use USB4 with external GPUs.
Table of Contents
USB4 vs Thunderbolt 3 vs Thunderbolt 4
USB4 uses the USB-C connector and has data transfer speeds of up to 40Gbps. It has similar functionality as Thunderbolt 3 and supports DisplayPort and DisplayPort Tunneling to use with an external graphics card. USB4 does not require an Intel-certified controller and is royalty-free. Note that while USB4 can support external GPUs, this mainly depends on the USB4 implementation. This is also true for Thunderbolt 3 compatibility and other features. Regarding speed, the minimum requirement for the USB4 standard is 20 Gbps. So, you might not get the full 40 Gbps transfer speed, despite having a USB4 interface.
Thunderbolt 3 also uses the USB-C connector and supports data transfer speeds of up to 40Gbps. Like USB4, Thunderbolt 3 supports protocols such as DisplayPort and PCIe for external GPUs. And it supports either a single 4K display at 120Hz, a 5K display at 60Hz, or two 4K displays at 60Hz. It is worth mentioning that some Thunderbolt 3 are limited to 20 Gbps so you should check the rated speed before buying. Thunderbolt 3 is proprietary to Intel and requires an Intel-certified controller.
On paper, Thunderbolt 4 has the same maximum speed as USB4 or Thunderbolt 3. It does require a controller and certification from Intel. The changes are oriented toward quality control since Intel further requires the Thunderbolt 4 standard to support the full 40 Gbps speed. So, you no longer need to worry about accidentally buying a cable that is limited to 20 Gbps. Furthermore, Intel requires Thunderbolt 4 to support two 4K displays or a single 8K display.
Image Credit: Intel
These ports also come with additional features such as support for accessories, PC charging, wake from sleep, and Thunderbolt networking.
While all three might have similar specifications on paper, Thunderbolt 4 is more reliable and has higher minimum specifications. While manufacturers can choose to cut costs by not implementing some features with USB4, Thunderbolt 4 doesn’t have any such provision.
If you are having trouble with Thunderbolt on Linux, you can check out our guide on how to use Thunderbolt 3 and 4 on Ubuntu.
Do USB4 eGPUS Exist?
Using an eGPU with a USB4 port depends on whether the implementation conforms to Thunderbolt 3 specifications. For example, AMD Ryzen 6000 series chips do not support Thunderbolt 3 even though they have USB4. Manufacturers need to add additional hardware to enable Thunderbolt 3.
If you are interested in using an external GPU with your laptop and cannot figure out the technicalities, then buy an Intel-based Thunderbolt laptop. But if you understand these technologies well and want an AMD-based laptop, you must ensure that the USB4 port supports the full 40Gbps transfer speeds. Moreover, if your laptop’s USB4 implementation allows it, you can use Thunderbolt 4 eGPU setups. Check out our recommended Thunderbolt eGPU enclosures to pair with your USB4-enabled AMD laptop.
Are USB4 Laptops Compatible With Thunderbolt 3 eGPUs?
Whether or not a Thunderbolt 3 eGPU enclosure will work with a USB4 laptop depends on the laptop manufacturer. Since PCIe tunneling and Thunderbolt 3 support are optional for the USB4 specification, there is no guarantee that the Thunderbolt 3 eGPU will work. It all comes down to the specific implementation of the USB4 port. The Apple M1 pro models, for example, are compatible with Thunderbolt 3 and Thunderbolt 4, but that might not be the case with other laptops.
Do Thunderbolt 4 eGPUs Exist?
External graphics card enclosures support Thunderbolt, such as the eGPU Breakaway Box 750/750ex. While eGPU enclosures can use Thunderbolt 4, as mentioned above, it has the same maximum speeds as Thunderbolt 3. Thunderbolt 4 ensures that you get better minimum transfer speeds of 40 Gbps and are not limited to 20 Gbps.
Jarrod’sTech tested the performance of an eGPU in different games and concluded that the performance improvement depends more on the CPU’s performance rather than the Thunderbolt implementation. Hence, you won’t experience performance loss using Thunderbolt 4 or Thunderbolt 3.
Do Laptop eGPUs Perform As Well As Dedicated Desktop Graphics Cards?
Dedicated graphics cards in laptops are not as powerful as their desktop counterparts since they are limited by power and the thermal design of the laptop.
So, are desktop graphics cards paired with laptops via eGPU enclosures on par with desktop graphics cards?
Jarrod’sTech tested a couple of games with eGPUs, compared them to desktop graphics cards, and found that the graphics cards used in a desktop perform better than cards connected to laptops via external GPU enclosures.
It all comes down to how much you value portability. You can turn a thin and light laptop, without a dedicated graphics card, into a gaming machine using an external graphics card enclosure. On the downside, an eGPU setup can be very expensive, and you might find that getting a mid-range laptop or desktop costs the same.
Do AMD Laptops Come Only With USB4?
Any laptop manufacturer can use Intel’s Thunderbolt standard under a licensing agreement. So, while you can find AMD-based laptops with Thunderbolt ports, they are uncommon. Thus, you can remain loyal to the AMD platform and still consider gaming using an eGPU setup using Thunderbolt.
Thunderbolt 3 support is optional for the USB4 specification, so using an eGPU with USB4 won’t always be possible. Sure, if you have the right USB4 implementation that offers a high PCIe bandwidth, you can have your pick of eGPUs and enjoy gaming on your ultrabook. But there are only a handful of options on the market that offer the said USB4 specifications.
So, it is improbable, and your best bet remains an Intel-based laptop with Thunderbolt 4 for connecting an eGPU. The market is filled with plenty of options to suit any budget.