Navigating the World of Thunderbolt 3 and USB-C: An In-Depth Guide
Introduction
If you‘ve purchased a laptop, smartphone, or other electronic device in the past few years, you‘ve likely encountered the oval-shaped USB-C connector. Some of these ports also support the Thunderbolt 3 standard which looks identical but offers additional capabilities. As someone who is passionate about the latest computing technologies, I often get asked about the differences between Thunderbolt 3 and USB-C. While they use the same physical connector shape, there are some key distinctions in their capabilities that are important to understand.
In this article, I‘ll provide an in-depth look at Thunderbolt 3 and USB-C. I‘ll compare their specifications, discuss their ideal use cases, and provide clarity on how to identify which standard a port supports. Whether you‘re a technology enthusiast or just trying to understand these interfaces, I hope you‘ll find this guide insightful. Let‘s jump in!
What are Thunderbolt 3 and USB-C?
Before diving into the differences, let‘s start with a basic overview of each:
USB-C
USB-C is the latest connector shape/port in the USB (Universal Serial Bus) standard. It was developed by the USB Implementers Forum (USB-IF), an industry group with members including Apple, Intel, Microsoft, and others. USB-C was first released in 2014.
The USB-C connector has an oval shape and is reversible, meaning it can be inserted either way up. This addressed a major pain point of previous USB connectors. USB-C cables can carry data, power, and display signals, consolidating multiple ports into one.
However, not all USB-C ports are created equal. The USB-C connector shape is also used by other standards like Thunderbolt 3 and DisplayPort Alt Mode. So just because a device has a USB-C port, doesn‘t necessarily mean it supports all USB-C capabilities.
Thunderbolt 3
Thunderbolt is an interface standard developed by Intel and Apple. It combines PCI Express and DisplayPort into a single connection and adds power delivery. Thunderbolt 1 and 2 used the Mini DisplayPort connector.
In 2015, Thunderbolt 3 was released, moving to the USB-C connector shape. This allowed Thunderbolt 3 ports to fallback to USB-C functionality, as well as expanding Thunderbolt‘s reach as USB-C became more common. Thunderbolt 3 still uses the underlying Thunderbolt transport layer, layered on top of the USB-C connector.
Thunderbolt 3 vs USB-C: Key Differences
Now that we have a basic understanding of each, let‘s compare their capabilities:
Data Transfer Speed
One of the key advantages of Thunderbolt 3 is its blazing fast data transfer speeds. Thunderbolt 3 supports speeds up to 40Gbps, double that of the fastest USB-C implementation (USB 3.2 Gen 2×2 at 20Gbps).
That means Thunderbolt 3 can transfer a 4K movie in less than 30 seconds. This speed advantage makes Thunderbolt 3 well-suited for transferring large files, working with high-res video footage, or performing frequent backups.
USB-C ports vary in their supported data speeds depending on the underlying USB specification:
- USB 3.2 Gen 2×2: Up to 20Gbps
- USB 3.2 Gen 2: Up to 10Gbps
- USB 3.2 Gen 1: Up to 5Gbps
While not as fast as Thunderbolt 3, these speeds are still very quick and sufficient for most users‘ file transfer needs. The original USB 1.0 had a maximum speed of 12Mbps, so USB has come a long way!
Power Delivery
Both Thunderbolt 3 and USB-C feature built-in power delivery capabilities, eliminating the need for a dedicated power cable in many cases. However, there are some differences in their implementations.
Thunderbolt 3 supports power delivery up to 100W. This allows you to charge power-hungry devices like a 15-inch MacBook Pro over a single Thunderbolt 3 cable. Thunderbolt 3 mandates a minimum power level of 15W for devices.
USB-C on its own defines a much lower minimum power level of 2.5W. But, when paired with USB Power Delivery specifications, it can also scale up to 100W. Many USB-C devices support Power Delivery today.
Both Thunderbolt 3 and USB Power Delivery intelligently negotiate the optimal power level between device and charger. They also implement numerous safety mechanisms to protect devices. With either standard, you can charge your laptop from a compatible USB-C charger instead of carrying around a bulky power brick.
Video Capabilities
Thunderbolt 3 and USB-C both have impressive display capabilities, but Thunderbolt 3 pulls ahead in this category too.
A single Thunderbolt 3 port can drive two 4K displays at 60Hz or a single 5K display. It achieves this by carrying DisplayPort video signals alongside PCIe data in its 40Gbps of bandwidth. Thunderbolt 3 also supports HDMI and VGA displays with the appropriate adapter.
USB-C ports can output video signals as well by leveraging DisplayPort Alt Mode or HDMI Alt Mode specifications. A USB-C port with Alt Mode can drive a single 4K display at 60Hz. This allows some USB-C laptops to connect to an external monitor without needing a dedicated video-out port.
For most people‘s needs, USB-C Alt Mode is a convenient solution for connecting an external display. But if you‘re a content creator or heavy multi-tasker wanting to run multiple high-res displays, Thunderbolt 3 is the way to go.
Daisy Chaining
Another unique feature of Thunderbolt 3 is the ability to daisy chain up to six devices from a single port. This allows you to connect displays, storage devices, and other peripherals without using up all your ports.
For instance, you could connect your laptop to a Thunderbolt 3 dock. That dock could then connect to two 4K displays, an external SSD, and an ethernet adapter. And you still have one port left for another peripheral if needed.
USB-C does not natively support daisy chaining. While you can use a USB-C hub to connect multiple devices, that hub can‘t then connect to another hub downstream. Thunderbolt 3‘s daisy chaining makes it appealing for workstations with lots of peripherals and limited ports.
Compatibility
A key difference between Thunderbolt 3 and USB-C is how widely each is supported. All Thunderbolt 3 ports are also fully functional USB-C ports. They can work with any USB-C cable or peripheral.
But the inverse is not true. Most USB-C ports do not support Thunderbolt 3. A USB-C device can only take advantage of Thunderbolt 3 speeds and features if it specifically says it supports Thunderbolt 3. And you‘ll need an active Thunderbolt 3 cable (not just a standard USB-C cable) to enable T3 capabilities.
Thunderbolt 3‘s reliance on PCIe signaling also means it will mostly be found in computers and devices with Intel processors. USB-C is processor-agnostic and can be implemented in any device.
USB-C is much more common today, with wide support across laptops, tablets, smartphones, and peripherals. Thunderbolt 3 is more of a premium feature reserved for high-end computers and professional equipment. But its adoption is growing as the technology matures.
Cost
The additional capabilities of Thunderbolt 3 do come at a cost. Thunderbolt 3 controllers, cables, and peripherals are often noticeably more expensive than their USB-C counterparts.
An active Thunderbolt 3 cable (required for full T3 speeds) costs around $50. Meanwhile, you can find USB-C cables for under $10 in many cases. Similarly, Thunderbolt 3 docks and drives often sell for a significant premium over USB-C ones.
For many individuals and businesses, the extra cost of Thunderbolt 3 is worth it for the improved performance. But if you don‘t need the absolute fastest speeds, USB-C offers a lot of value and more affordable options.
Identifying Ports
Since Thunderbolt 3 and USB-C share the same port shape, it can be tricky to identify which standard a port supports.
The foolproof way is to check the device‘s technical specifications or manual. But there are also some visual clues you can look for:
- Thunderbolt 3 ports often (but not always) have a small lightning bolt icon next to the port
- Thunderbolt 3 ports are always accompanied by the USB SuperSpeed logo (SS with a 10 inside)
- USB-C ports without Thunderbolt 3 won‘t have the lightning bolt icon
If you see a USB-C port without a lightning bolt, it‘s safe to assume it‘s a standard USB-C port (not Thunderbolt 3). When in doubt, consult the device‘s documentation.
The Future: USB4 and Thunderbolt 4
The worlds of Thunderbolt and USB will converge even more with the recently released USB4 and Thunderbolt 4 standards.
USB4, released in 2019, essentially integrates Thunderbolt 3 capabilities into the USB standard. It offers speeds up to 40Gbps, display connectivity, and backwards compatibility with Thunderbolt 3 devices. This promises to bring more unification and less confusion to these interfaces going forward.
Thunderbolt 4, detailed in 2020, is a relatively minor update focused on increased minimum performance requirements. It will continue to use the USB-C connector and be cross-compatible with Thunderbolt 3 and USB4.
As these next-gen interfaces roll out, we can expect to see more devices taking advantage of their unmatched speed and flexibility.
Conclusion
So, which is right for you? The choice between Thunderbolt 3 and USB-C depends on your needs:
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For the absolute fastest speeds, daisy chaining displays, and maximum performance, go with Thunderbolt 3 – if your devices support it and your budget allows
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For most users, USB-C is a more accessible and budget-friendly interface. It does everything that most people need on a day-to-day basis and has much broader device compatibility
If you have mission-critical work requiring Thunderbolt 3‘s capabilities, by all means take advantage of it. But don‘t feel like you‘re missing out if you only have standard USB-C devices. USB-C is an incredibly capable interface that has ushered in a new era of consolidated, reversible, and powerful ports.
As we look ahead to Thunderbolt 4 and USB4, the future looks bright for these interfaces. We can expect to see the best of both worlds – Thunderbolt-level performance with USB ubiquity and affordability. It‘s an exciting time in the computing world!
I hope this in-depth look at Thunderbolt 3 and USB-C has been helpful. While the differences can seem nuanced, understanding these technologies is increasingly important as they become central to our devices. If you have any other questions, feel free to ask. I‘m always eager to discuss the latest trends and help unravel these technical complexities.
