Thunderbolt 3, USB Type-C, and eGPU Connectivity: What You Need to Know

In the world of tech, there's a lot of confusion around connectivity standards, especially when it comes to integrating external graphics processing units (eGPUs) with laptops that don't come equipped with the latest and greatest ports. In this article, we'll explore the limitations and intricacies of connecting a USB Type-A to Type-C, then to Thunderbolt 3, and finally to an eGPU.

Understanding the Ports and Standards

In order to effectively utilize an eGPU, it's important to understand the specifications and capabilities of the different ports and standards. Thunderbolt 3, USB Type-C, and regular USB have distinct characteristics that impact their suitability for transferring data, especially when it comes to video and graphical processing.

Thunderbolt 3: Thunderbolt 3 is one of the most versatile ports available, offering both high-speed data transfer and power delivery. It can support multi-display setups, streaming, and even charging. However, for video processing tasks, especially those requiring substantial bandwidth, Thunderbolt 3's 40 Gbps throughput is crucial.

USB Type-C: USB Type-C is a newer standard that supports various protocols including USB 3.2, Thunderbolt 3, and DisplayPort Alternate Mode (DP Alt Mode). It offers reversible plugging and improved power delivery. However, while USB 3.2 is a significant upgrade over earlier USB standards, it still falls short in terms of bandwidth for demanding graphical processing tasks.

Regular USB: Regular USB ports, such as USB Type-A, typically offer speeds of 12 Mbps for USB 2.0 or 5 Gbps for USB 3.1. These speeds are far too slow to meet the demands of modern eGPUs, which require significantly higher bandwidth to perform effectively.

The Limitations of Multi-Port Solutions

Your friend's proposed setup involves a multi-step conversion from USB Type-A to Type-C, then Thunderbolt 3, and finally to the eGPU. However, as we'll discuss, this approach is fraught with limitations primarily due to the bandwidth constraints of USB Type-A and the need for a Thunderbolt 3 host controller.

USB Type-A to Type-C: Even if a USB Type-A connector is connected to a USB Type-C cable, the performance is still limited by the slower USB Type-A standard. This means that the entire chain remains limited by the slowest link, in this case, USB Type-A.

No Thunderbolt 3 Host Controller: Thunderbolt 3 connectivity is essential for high-end performance with eGPUs. Without a Thunderbolt 3 host controller, you are essentially using a common USB 2.0 or USB 3.1 port, which simply doesn't have the bandwidth required to power an eGPU.

Alternatives and Recommendations

For those looking to set up an eGPU system, it's crucial to consider the host controller. Thunderbolt 3 is recommended due to its 40 Gbps throughput, which is necessary for high-performance eGPUs. Here are some recommendations for achieving a workable setup:

Thunderbolt 3 on Laptop: Opt for a laptop that has Thunderbolt 3 ports. Most recent laptops feature Thunderbolt 3, making them an excellent choice for eGPU integration. Thunderbolt 3 to eGPU Adapter: Consider using a Thunderbolt 3 to eGPU adapter. These adapters provide the necessary interface for eGPU integration without the need for a separate Thunderbolt 3 cable for power delivery. Thunderbolt 3 Hub: For those with older laptops, a Thunderbolt 3 hub can provide the necessary Thunderbolt 3 port. These hubs typically cost less than a dedicated Thunderbolt 3 laptop but still offer the critical bandwidth.

The Future of eGPU Connectivity

As technology continues to advance, we're seeing an increasing focus on Thunderbolt 3 and USB Type-C as the go-to standards for high-bandwidth applications. The adoption of these standards in newer laptops means that setting up and managing an eGPU is becoming more straightforward. Moving forward, it's likely that Thunderbolt 3 will become the de facto standard for eGPU integration, offering both high speeds and robust power delivery.

While USB Type-C can work in certain scenarios, it's important to note that its performance is still limited by the base USB standard unless it's specifically configured for Thunderbolt 3.

Conclusion: In summary, while it is possible to set up an eGPU using a USB Type-A to Type-C connection and possibly a Thunderbolt 3 to eGPU adapter, the performance will be significantly hampered by the limitations of the USB Type-A port. For the best results, a direct Thunderbolt 3 connection or a Thunderbolt 3-based adapter is essential. Always ensure that your setup includes a Thunderbolt 3 host controller to fully leverage the capabilities of your eGPU.