Computer connections have become quite confusing, especially with new versions of the USB standard. With the latest standard USB4, confusion has been largely eliminated and significant improvements have been made. You can find all the details about USB 3.0, 3.1, 3.2 and 4.0 connections in our article here. On the other hand, there is the Thunderbolt connection technology, which continues to evolve.
Offering cross-compatibility with Thunderbolt 3 and 4, USB4 supports connections up to 40 Gbps. USB4 version 2.0 increases the maximum speed to 80 Gbps. But for high resolution monitors, the bandwidth can go even higher, up to 120 Gbps in one direction (with 40 Gbps downlink).
Thunderbolt 4 is built on the USB4 standard and will work backwards compatible with previous generations of Thunderbolt and USB products. Now we’re bringing together key details about the Thunderbolt 4 standard and compatible products.
What is Thunderbolt?
Thunderbolt is a connection protocol that offers fast data transfer, high-definition video streaming and charging support at the same time. Earlier generations of the Thunderbolt standard used a Mini DisplayPort connector, while Thunderbolt 3 and Thunderbolt 4 use the more capable USB-C connector.
What is Thunderbolt 4?
Introduced by Intel as a universal connectivity experience, Thunderbolt 4 (TB4) is a “superstandard” that includes USB4, DisplayPort, and PCI Express (PCIe). There is no big difference in terms of performance. As for the biggest difference, laptop, peripheral, and cable manufacturers will now need to meet more and more standards for Thunderbolt 4 certification. In this context, when you want to buy a Thunderbolt 4 supported product, you can at least make sure that the following features are met:
- 40 Gbps data transfer rate over cables up to 2 meters (6.5 feet) in length.
- 32 Gbps PCIe data transfer (twice as Thunderbolt 3).
- Support for two 4K displays (or one 8K display).
- At least one port that supports 100W laptop charging.
- Enhanced wake-up support for devices.
Thunderbolt 4’s USB4 support promises to bring order to the fragmented world of USB cables and devices. A Thunderbolt 4 capable laptop or dock allows the use of Thunderbolt 4, Thunderbolt 3, USB4, USB 3.x and USB 2.0 devices.
Is Thunderbolt 4 the Same as USB-C?
Thunderbolt ports and connectors are marked with the “lightning bolt” logo, and sometimes the version of the supported Thunderbolt standard is also indicated.
Thunderbolt 3 vs. 4
| Thunderbolt 4 | Thunderbolt 3 | |
| Data transfer | 40 Gbps | 40 Gbps |
| Video Streaming Support | Two 4K monitors Single 8K monitor | Two 4K monitors Single 8K monitor |
| Power/Charge | up to 100W | up to 100W |
| Daisy Chain | up to 6 devices | up to 6 devices |
| Cable Length | 2 m | 0.5 m |
| Connector | USB-C | USB-C |
Important points
Can I plug a USB-C device into the Thunderbolt 4 port?
Yes. A Thunderbolt port will communicate with the connected device regarding data rate, power, and video capabilities and will “fall back” to the USB protocol if the device is not Thunderbolt-capable. This fallback mode also allows a Thunderbolt device to be connected to a non-Thunderbolt USB-C port and still work, albeit at USB3 level.
Is a Thunderbolt monitor different from a USB-C monitor?
Thunderbolt supported monitors have a USB-C Thunderbolt port. Thunderbolt allows you to daisy chain two 4K monitors. Therefore, the monitor used will need two Thunderbolt ports, one for the signal from the host and the second for transferring the video to the second monitor. Thunderbolt powered monitors can also charge a high wattage device such as a laptop computer.
Can I plug the USB-C cable into the Thunderbolt 4 port?
Yes. Thunderbolt 4 ports are suitable for any cables that carry a USB-C connector. However, to take advantage of Thunderbolt performance, you need to connect one Thunderbolt device to another, such as a Lenovo Yoga 9i laptop to a Thunderbolt-enabled monitor or docking station.
Thunderbolt’s History
Intel introduced Thunderbolt in 2009 under the codename Light Peak. A copper-based version, originally designed as an optical interface, was jointly developed by Apple and Intel a
With the new versions introduced later, the data transfer rate, connection type and power supplied have also changed. The latest Thunderbolt 4 release offers support for two 4K@60Hz or one 8K@60Hz displays.
Thunderbolt Connectors
Features of USB-C cables can vary, so it’s important to look at the details when purchasing any product. Although both Thunderbolt and USB ports accept USB Type-C cables, only Thunderbolt-specific cables can be used for Thunderbolt connections. Thunderbolt cables can also be used for full-featured USB connections, meaning they’re designed to work with any USB-C port.
Thunderbolt cables provide four shielded SuperSpeed pairs known as “lanes”, each capable of carrying data packets at 20 Gbps.
The Thunderbolt port dynamically detects the characteristics of attached cables and devices, while automatically activating one (or more) of five connection modes:
- USB Mode Only: For USB devices or cables that do not support Thunderbolt, the Thunderbolt port enables the USB controller to support USB 3.x or 2.0 signaling.
- Thunderbolt Alt Mode: When a Thunderbolt cable and device are connected, the Thunderbolt controller combines two lanes in each direction to create two full-duplex, bi-directional 40Gbps channels.
- DisplayPort Alt Mode: When a DisplayPort monitor or adapter is plugged into the Thunderbolt port, the controller activates DisplayPort Alt Mode, remapping all four USB-C lanes to work in one direction, creating a single 80Gbps link fast enough for an 8K HDR2 display.
- USB/DP Combo Mode: Shares four USB-C lanes between DisplayPort and USB, along with a combination of USB and DP modes described above.
- Thunderbolt Network Mode: Allows two or more Thunderbolt-enabled computers to establish a direct Ethernet connection to share resources and copy, transfer or print files.
- Power Delivery and Charging: Power and charging of host and attached devices are supported by USB-PD in addition to the 15W available for bus powered peripherals.
Passive and Active Cables
There are two variants of Thunderbolt 3 cables: passive and active. Passive cable transmits electrical signals over copper wire without any interference to strengthen the signal. Active cable, on the other hand, is supported by the transceiver at both ends to regulate data transmission over the cable, allowing transmission over longer distances.
Passive Thunderbolt 3 cable can transmit data at a rate of 40 Gbps over a distance of 0.5 meters. Data transmission at 2 meters is limited to 20 Gbps. As a result, you need an active Thunderbolt 3 cable for a maximum data throughput of 40 Gb/s up to 2 meters. With the launch of Thunderbolt 4, passive cables will be able to transmit data at 40 Gbps up to 2 meters.
Thunderbolt Features
Data transfer
Thunderbolt 4’s maximum bandwidth is 40 Gbps. However, this is somewhat misleading because not all of this bandwidth can be used for data transfer. About 8 Gbps can be used for video streaming only, while the remaining 32 Gbps (PCIe 3.0: 4 lanes x 8 Gbps) is used for other operations.
Taking into account PCIe 8b/10b encoding and Thunderbolt 4’s own overhead, you’ll get a peak throughput of around 22 Gbps. In other words, even if it is not 40 Gb / s in total, the speeds are still high. Such high data transfer rates allow us to use products such as SSD and connected external graphics solutions (eGPU).
Why am I not getting the full 40Gbps speed from my Thunderbolt 4 connection?
- Does the USB-C port have the “lightning bolt” logo? If not, you may be using a slower USB port.
- Does the peripheral (monitor, dock, storage) support Thunderbolt 4? If it’s a USB device, Thunderbolt starts using USB speeds.
- Are there any other devices connected to the Thunderbolt 4 port? You can guess that the devices will share the available bandwidth. For example, a 4K display will consume around 14Gbps and leave 26Gbps for data with no video output.
Video
Thunderbolt 4 includes support for DisplayPort 2.0, which allows it to power up to three 10K monitors or 16K monitors at 60Hz simultaneously. Thunderbolt 3, on the other hand, supports DP 1.4 with enough bandwidth to support two 4K (3840 x 2160) displays at 60 Hz, a single 4K display at 120 Hz, or a single 5K display at 60 Hz.
Networking
Thunderbolt Networking allows peer-to-peer communication between two or more computers via a Thunderbolt cable. This function is very useful for sharing resources and moving large amounts of data between computers.
Power & Charge
Thunderbolt 3 supports USB Power Delivery (PD-USB Power Delivery) and allows the port to supply up to 100W of power; This is very important because it eliminates the need for an AC power adapter required for some devices. However, not all device manufacturers may add USB-PD support.
Thunderbolt 3 can also provide 15W of power to connected bus-powered devices such as external hard drives, cameras, and portable monitors. This value is enough to charge a tablet or smartphone.
Advantages of Thunderbolt 4
Multi-Monitor Setup
If your laptop has a Thunderbolt 3 or Thunderbolt 4 port, you have a few options to consider:
- Daisy Chain: We can summarize this briefly as the ability to connect the monitor to the monitor. We can connect a Thunderbolt-enabled monitor to the laptop’s Thunderbolt port, and then the second monitor to the first monitor. To do this, the graphics card must support Multi-Stream Transport (MST). Daisy chain is not limited to monitors. You can chain external storage and other laptops for up to 6 devices in total. Thunderbolt is bidirectional, so your laptop can send a video signal to an external monitor, while the monitor can send power to charge your laptop.
- Display Connection Adapter: You can connect two DisplayPort monitors to your laptop’s Thunderbolt port with the help of adapter. You can get a resolution of 4K(3840 x 2160)@60Hz in a dual-screen setup or 5K(5120 x 2880) at 60Hz on a single screen.
- Thunderbolt Hubs: In addition to other useful features such as connecting to an Ethernet network or accessing a flash drive, docks and hubs often offer some video connectivity options. For example, custom hubs can output two 4K@60Hz monitors or one 8K@30Hz monitor.
External Storage
If you regularly work with video files or have a large music or photo library, you may want to consider adding external storage to your laptop. Enough for USB 3.0 and USB 3.1 external hard drives (HDD). However, if you want to use a fast SSD, you should go for the USB 3.2 (20 Gb/s) or Thunderbolt 3 (40 Gb/s) interface. External SSDs are times and times faster than HDDs, with sequential read/write speeds of up to 2,800/2,300 MB/s.
External Graphics (eGPU)
A variety of external graphics (eGPU) solutions are available, including the power supply and slots for a full-size PCIe graphics card. Those who want to bring desktop-class graphics performance to Windows 10 or Mac laptops can resort to such solutions. eGPU cases are generally of interest to gamers, video and graphics editors.
eGPU setup needs a fast connection to connect external video cards to laptop; This is where Thunderbolt, which offers high bandwidth, comes into play.
Cable Clutter
Laptop users are drowning in cables when it comes to power adapters, external monitors, additional storage and USB devices. Thunderbolt ports make everything simpler by consolidating all connections into one Thunderbolt cable.
Data Transport
The Thunderbolt IP network lets you connect two Mac or Windows computers and set up a full duplex 10Gb Ethernet connection. If you’re using a Mac computer, you also have an option called Target Disk Mode.
The New Thunderbolt Standard
Following the release of USB 4 version 2, Intel provided new details about the feature set presented by the USB Implementer Forum and its Thunderbolt technology that will be compatible with DisplayPort 2.1. It was previously reported that the new version will provide twice the bandwidth (80 Gbps) compared to Thunderbolt 4. Now, technologies that enable tremendous speeds such as 120 Gbps have been exhibited.
Previously, this standard was branded together with the names Thunderbolt, Thunderbolt 2, Thunderbolt 3, and Thunderbolt 4. Intel still hasn’t specified a name for the new standard, but we expect it to be Thunderbolt 5. The upcoming link technology uses its lanes equally for both data transmission and data retraction at up to 80 Gbps simultaneously. But when the connectors are connected to a more bandwidth-hungry display (perhaps an 8K monitor), the new interface allows full speed usage while taking over some of the transmission-based connectivity.
USB-IF recently announced a similar asymmetric signal interface to provide 120 Gbps transmission speed. Offering cross-compatibility with Thunderbolt 3 and 4, USB4 supports connections up to 40 Gbps. USB4 version 2.0 increases the maximum speed to 80 Gbps. But for high resolution monitors, the bandwidth can go even higher, up to 120 Gbps in one direction (with 40 Gbps downlink).
Intel says Thunderbolt provides “compatibility” with the latest USB version. The next-generation standard will support speeds of up to both 80 Gbps and 120 Gbps for certain video workloads. The slide shared by the company shows all the “optional” features in USB 4, including speeds over 20 Gbps. In short, Intel claims that if you use Thunderbolt you will get a better experience with more guaranteed results.
The new Thunderbolt connectors will work with commercially available passive cables up to one meter long. It is also designed to support up to twice the PCI Express data throughput over previous specifications to enhance the gaming experience achieved with GPU connections.
