Thunderbolt 3 Explained: Why You Need the World's Fastest Port

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If you want to connect your notebook to multiple 4K displays, attach a graphics amp, transfer giant files to the fastest external drives or grab RAW video from an expensive camera, you should get Thunderbolt 3. With a maximum speed of 40 Gbps, it's the fastest port on the market today. In the past six months, we've seen a steady stream of new laptops and 2-in-1s with Thunderbolt 3 ports on board while more peripherals and docks come to market. If high-speed connectivity matters to you, you'll want to make sure your next system supports this powerful standard.

Here are eight things you need to know about Thunderbolt 3.

Thunderbolt 3 Explained: Why You Need the World’s Fastest Port

1. 4x the Speed of the Fastest USB Connection

Thunderbolt 3 is capable of transmitting at a rate of 40 Gbps, which is a lot quicker than USB 3.1's rate of 10 Gbps or USB 3.0's limit of 5 Gbps. It's also double the bandwidth of Thunderbolt 2 (20 Gbps). With that kind of throughput, you can attach a graphics amplifier like the Razer Core and turn your lightweight laptop into a bona-fide gaming rig, because the system can contact the GPU at the same speed as if it were attached directly to the motherboard.

Thunderbolt 3 vs Other ports. Image Courtesy of Intel

You can copy files to a speedy external SSD that's faster than most internal drives. The same benefits apply when you're recording directly from a professional-grade 4K video camera.

2. Uses USB Type-C Connectors

All Thunderbolt 3 ports are also USB Type-C 3.1 ports and use the Type-C's thin, reversible connector. You can connect any USB Type-C device to any Thunderbolt bolt, because technically, Thunderbolt is an "alt mode" for USB. However not all USB Type-C ports and wires support Thunderbolt 3. For example, the Apple MacBook and Lenovo ThinkPad 13 have USB Type-C ports that don’t support the faster standard, but the HP EliteBook Folio G1 and Dell XPS 13 do have Thunderbolt 3.

wire with lightning bolt logo. Image courtesy of Intel

MORE: USB Type-C FAQ: Everything You Need to Know

3. Connects to Two 4K Monitors at Once, Using DisplayPort

Thunderbolt 3 can transmit video via the DisplayPort (DP) 1.2 standard, but one-ups DP by offering two connections in a single wire. So while, a single DP 1.2 cable can handle only one 4K monitor while running at 60 Hz, a single Thunderbolt 3 connection can output to two 4K monitors at 60 Hz, one 4K monitor at 120 Hz or one 5K (5120 x 2880) monitor at 60 Hz.

HP Elite Thunderbolt Dock


You can connect from a Thunderbolt 3 port directly to a single monitor, using a Thunderbolt-to-DisplayPort cable. However, if you want to use multiple monitors over a single cable, you'll need a Thunderbolt dock like the Dell Thunderbolt Dock or HP Elite Thunderbolt 3 dock.

MORE: Best Laptop Docking Stations

4. High-Speed, Peer-to-Peer Networking

You can connect two PCs together using a single Thunderbolt 3 port and get a 10Gb Ethernet connection. That's 10 times faster than most wired Ethernet ports. So, if you need to quickly copy a giant file to your co-worker's laptop, you'll be able to do it at really high transfer rates.

Thunderbolt wires can be used in peer-to-peer networking. Image courtesy of Intel.

5. Tiny Lightning Bolt Logo Helps You Find Compatible Products

How do you know if a port, wire or peripheral supports Thunderbolt 3, rather than plain USB 3.1? Look for a tiny lightning-bolt logo on the plugs of a wire or near the connector on a laptop or peripheral. Uncertified products are not allowed to use the logo.


Thunderbolt Branding. Image Courtesy of Intel

Unfortunately, while Intel, which runs Thunderbolt, encourages companies to use the logos, they aren't required. The Razer Blade Stealth is one example of laptop that has a Thunderbolt 3 port with no label.

Razer Blade Stealth has no label on its Thunderbolt 3 port

6. Enough Power to Charge Most Laptops

Because they use the USB Power Delivery standard, Thunderbolt 3 ports can send or receive up to 100 watts of power, which is more than enough to charge most laptops. Indeed, on some superthin laptops, like the HP EliteBook Folio G1 and the Razer Blade Stealth, the Thunderbolt 3 port is the only A/C port.

HP Thunderbolt 3 ports are clearly labeled and can charge it.

However, workstation and gaming-class laptops such as the Lenovo ThinkPad P70 or Asus G752 require a lot more than 100 watts. Thunderbolt 3 can also deliver up to 15 watts of electricity to bus-powered devices. So, external hard drives, cameras and portable monitors can consume a lot more juice.

7. Graphics Amps Not Guaranteed to Work with Every System

Though they use a standard Thunderbolt 3 connection, first-gen graphics amps aren't made to work with every Thunderbolt-enabled PC. The Razer Core, for example, is certified to work only with the company's own laptops and with Intel's Skull Canyon NUC mini PC. Asus only guarantees that its upcoming XG Station 2 will work with Asus-branded laptops. However, if a PC vendor hasn't specifically blocked these amps, it is possible that they would work on an unsupported notebook. Hopefully, in the near future, we'll see graphics amps that are built from the ground up to work with any computer that has a Thunderbolt 3 port.

Asus XG Station 2

8. Daisy Chain Up to 6 Devices

You can connect up to six different computers and accessories to each other using Thunderbolt 3 cables. Imagine connecting your laptop to a high-speed hard drive then sending another wire out to a monitor and a third wire from the monitor to a high-speed camera. If all the devices in the middle of the chain have two ports (one for in and one for out), you can do it.

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Author Bio
Avram Piltch
Avram Piltch, LAPTOP Online Editorial Director
The official Geeks Geek, as his weekly column is titled, Avram Piltch has guided the editorial and production of since 2007. With his technical knowledge and passion for testing, Avram programmed several of LAPTOP's real-world benchmarks, including the LAPTOP Battery Test. He holds a master’s degree in English from NYU.
Avram Piltch, LAPTOP Online Editorial Director on
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