Intel has stated that this next-generation Thunderbolt will deliver 80Gbps (gigabits per second) of bi-directional bandwidth (40Gbps + 40Gbps) and, when across three lanes at 40Gbps each, would enable up to 120Gbps for the best video-intensive display experience.
Thunderbolt 5’s new speeds are therefore up to three times that of Thunderbolt 4.
This is an especially significant increase, given that Thunderbolt 4 didn’t even nudge up bandwidth when it succeeded Thunderbolt 3 in 2020. Thunderbolt 4 was more about setting common standards than speed increases.
See also: Thunderbolt 4 vs Thunderbolt 3 vs USB-C
According to Intel’s Ziller, next Thunderbolt will automatically switch from 80Gbps operation to 120Gbps only when connected to a display requiring more than 80Gbps—for example with 8K HDR monitors or a 4K display at 240Hz.
A bandwidth-hungry display is “really the most important thing that’s going to have very high bandwidth needs that are only going in one direction,” said Ziller. Storage data transfer is typically bidirectional in nature.
Intel has previously mentioned using “80G PHY Technology”, which refers to the physical layer.
Getting more technical, the PHY is based on “a novel PAM-3 modulation technology”.
This is all about how the 0 and 1s are transmitted. Traditional NRZ encoding allows for a 0 or a 1 to be transmitted (that is, a single bit). A scheme that allows two bits to be transferred is called PAM-4 (Pulse Amplitude Modulation).
However, what Intel is working on is “PAM-3”, which is a technology where the data line can carry either a -1, a 0, or a +1. PAM-3 signal encoding uses three bits of data per clock cycle instead of two bits.
80-120Gbps is pretty special when you consider that the average data speed of USB-C is 5Gbps and a million miles from USB 2.0’s 480Mbps.