At present, the mainstream transmission interface standards in the market are thunderbolt, USB and eSATA. This paper attempts to clarify these dazzling terms and deepen readers’ understanding of digital knowledge.

Analysis of current mainstream transport interface standards thunderbolt, USB and eSATA

What is the difference between thunderbolt 2 and thunderbolt 1?

The second-generation thunderbolt standard combines DisplayPort and PCI Express specifications, and has a faster data transmission rate than the first generation thunderbolt. The former can transmit 4K video data through a single connection channel, twice the speed of the first generation, but their bandwidth is 40Gbps.

The difference between the two lies in the allocation and utilization of bandwidth. The original thunderbolt standard supports four one-way channels, each providing 10Gbps bandwidth, two for uplink data transmission and two for downlink.

Thunderbolt 2 provides two bidirectional channels, each with 20gbps bandwidth, which means that a single channel can meet the transmission requirements of 4K video or high-speed storage devices.


All three standards are far better than USB2.0 in transmission rate. The maximum speed of USB2.0 is 480mbps, eSATA supports 6gbps (the old version is 1.5gbps or 3gbps), USB3.0 is 5Gbps (the upcoming usb3.1 will support 10Gbps), and thunderbolt is 20gbps.


Analysis of current mainstream transport interface standards thunderbolt, USB and eSATA

Thunderbolt combines two interface standards: PCI Express and DisplayPort, which means users can connect displays, external drives, video capture devices, and so on. DisplayPort provides backward compatibility, but users need a cable adapter to use the existing DisplayPort port. At the same time, through the adapter, thunderbolt can also connect to DVI, HDMI and VGA displays. In addition, if users use OSX, they can network two Macs through thunderbolt instead of traditional Ethernet ports.

The connector of thunderbolt 2 is consistent with the original thunderbolt standard. Therefore, the user can connect the thunderbolt device to the thunderbolt 2 port, and vice versa, and the connector can also be universal. Similar to other standards, the connection mode with the old specification will not benefit from the performance improved by the new standard.

It should be specially pointed out that if users are connected to thunderbolt and thunderbolt 2 devices in the same link (daisy chain), please ensure that the old thunderbolt devices are located at the end of the link, otherwise all devices will slow down to thunderbolt standard operation.

USB3.0 also provides backward compatibility, so users can connect USB2.0 devices to USB3.0 ports and vice versa. Of course, USB2.0 devices or ports cannot provide the speed of USB3.0. If users need to use multiple USB devices, they need multiple USB ports or purchase USB hubs. USB device is designed for independent use, without the daisy chain mode of thunderbolt device.

ESATA is an external version of serial ATA, which is usually used as a high-speed interface standard for built-in hard disks. Some companies, including Toshiba, have introduced notebooks with dual-mode port design, which can connect eSATA or USB devices at the same time.


Analysis of current mainstream transport interface standards thunderbolt, USB and eSATA

At present, thunderbolt 2 is largely limited to the recently launched Apple computers, such as MacBook Pro retina screen version, MacPro, 5kimac and 2014 macmini. It can also be found on a few PC port adapters. At the same time, there are a few exceptions. For example, Dell’s precisionm3800 workstation provides thunderbolt 2 port for professional users.

In comparison, USB3.0 is more common. Users can find it in a large number of PCs and PC peripherals, largely to replace eSATA ports on various peripherals, such as external hard disk. However, eSATA is still very popular among enterprise customers. The main reason is that the USB port is usually shut down by IT department for security reasons. Therefore, all kinds of external devices need eSATA port as a means of connection.

Although thunderbolt is still in the minority, the situation is likely to change. Thunderbolt 3 will have a unified port with usbtype-c, and is compatible with usb3.1 standard. It not only supports DisplayPort, HDMI and USB, but also provides data transmission rate up to 40Gbps and bidirectional power supply capability.

Intel said that more than 30 PC products will support thunderbolt 3, and the interface is expected to be unified.

Which one suits you best?

ESATA is most suitable for connecting PCs to external storage devices, especially for enterprise IT departments. However, for ordinary consumers, USB3.0 is more common and cheaper.

The price of thunderbolt is not cheap. It’s mainly for people who are engaged in 4K video editing, need high-speed data transmission rate, and who can’t even blink their eyes when facing the price of a 2m connecting line as high as 500 yuan.

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