Thunderbolt: Comparison Between All Its Versions

Thunderbolt is the name that Intel and Apple gave to an interface originally developed to allow the connection of external devices to a PC. Since its inception in 2011 there have been different versions (Thunderbolt 1, Thunderbolt 2, etc.), so in this article we are going to tell you about the differences and limitations that each one has.

Thunderbolt controllers multiplex one or more individual data lanes from connected PCIe and DisplayPort devices for transmission through two lanes in duplex mode, which are then demultiplexed for use by these PCIe and DisplayPort devices at the other end. A single Thunderbolt port supports up to six devices through hubs or hubs, as well as in Daisy-Chain mode (daisy-chaining each other), all using a single cable.

Thunderbolt: Comparison Between All Its Versions

Differences between Thunderbolt versions

Thunderbolt 1 Thunderbolt 2 Thunderbolt 3 Thunderbolt 4
Connector type Mini DisplayPort Mini DisplayPort USB-C USB-C
Pins twenty twenty 24 24
Bitrate 2×10 Gbps (20 Gbps total) 20 Gbps 40 Gbps 40 Gbps
Protocols 4 × PCI Express 2.0 DisplayPort 1.1a 4 × PCI Express 2.0 DisplayPort 1.2 4 × PCI Express 3.0
DisplayPort 1.2 (2 channels)
USB 3.1 Gen 2
4 × PCI Express 4.0
DisplayPort 1.2 (2 channels)
USB 4
Hot Plug Yes Yes Yes Yes
Daisy chain Yes, up to 6 devices Yes, up to 6 devices Yes, up to 6 devices Yes, up to 6 devices

Looking at the table it is obvious that the improvements in this interface have been coming two by two; While the V1 and V2 versions used Mini DisplayPort as a connector, from V3 the new reversible USB-C connector began to be used, something that will be repeated in the fourth version. The same is true for the bandwidth of each of these versions, from 20 Gbps in the V1 and V2 versions, it doubled in V3 and will remain in Thunderbolt 4.

This seems strange because the new V4 interface will take advantage of the enormous bandwidth that PCI-Express 4.0 offers , but they have considered that the latest revision does not need more bandwidth but more compatibility with more devices and more capacity to provide power, which is what modern external devices demand.

The importance of cables

There is a very important fact regarding the cables, and that is that in the first two revisions of the interface, which had a Mini DisplayPort connector, the cables could be either copper or optical, the former having a maximum length of only three meters but seconds up to 60 meters. Starting with Thunderbolt 3, they stopped offering optical cables, which is why the possible distance between devices was greatly reduced.

This is why many professional studios maintain old equipment with the interface V2, since in many of them they have PCs, servers and devices in a room other than the workplace where they have the screens (for example in a sound study, in order to avoid noise and interference) so those three meters are clearly insufficient.

Thunderbolt 1 and 2

Initially this technology was called Light Peak , but it was in February 2011 when the first device that incorporated it appeared, already with its commercial name and that we all know. It was the MacBook Pro of those times, which were followed in May 2011 by the iMac, and since then they continued to use it in all the devices that were launched on the market.

In those days it was certainly confusing to know what type of port each device had, since the connector was Mini DisplayPort. To find out, you had to look at the symbol: if it was a screen, it was only DisplayPort for video, but if it was lightning, it was Thunderbolt and it was used for video, audio and data interchangeably.

Puertos Thunderbolt

The second revision of the interface was announced in June 2013 along with Intel’s Falcon Ridge controllers, which promised the same 20 Gbps of the first version but with broader compatibility and the ability to power devices. In other words, they already allowed connecting an external hard drive, for example, without the need for additional power.

This was made possible by combining the two 10Gbps channels from the first review into a single channel with 20Gbps of bandwidth. In addition, Thunderbolt 2 added support for DisplayPort 1.2 , which meant that you could finally use a single 4K resolution monitor or two QHD resolution monitors. Finally, this revision was fully compatible with the previous one, so the new equipment models were compatible with the old peripherals.

Thunderbolt 3 and 4

With this new revision the Mini DisplayPort connector was replaced by the new generation reversible USB-C, and at the same time the bandwidth was doubled from 20 to 40 Gbps (5 GB / s), more than enough to expand the connectivity options (PCIe 3.0 4-lane, DisplayPort 1.2 8-lane and USB 3.1 10 Gbps). Support for this version was added with Intel Skylake processors.

intel-thunderbolt-4

Devices supporting this third interface revision began arriving in December 2015, including Windows laptops and even desktop PC motherboards with passive USB-C connectors.

In January 2018, Intel announced an improved version of the interface that would come with Titan Ridge that added support for DisplayPort 1.4 , and unlike previous revisions, this one stopped offering optical cables, so the maximum length of these was seen. reduced from a maximum of 60 meters to just 3 meters .

As for the fourth revision of the interface, its release has been delayed on several occasions because they were waiting for the PCI-Express 4.0 implementation at once. Maintains V3 bandwidth and adds full support for all USB 4 features.

In general and answering the question in the title of this article, improvements to the Thunderbolt interface are worth two to two, that is, there was a very important change between versions V2 and V3, but not between V1 and V2 and between V3 and V4.