Intel spills the beans about 80Gbps Thunderbolt 5

Via Twitter, Intel Client Computing Group chief Gregory M Bryant shared some Thunderbolt-related photos from a visit to Intel's facilities in Israel. In his initial post, there were a total of four photos, but it seems he spilled a bit too much details as the current version of his tweet contains just three pictures.

Next Thunderbolt supports 80Gbps and PAM-3

Fortunately, AnandTech was quick enough to take a screengrab. The deleted photo is the juiciest one of course, it contains a couple of details that shouldn't be out in the open just yet.

The meat here is that Thunderbolt 5 will support 80Gbps connections, double as much as what's currently possible with Thunderbolt 4. Secondly, Intel's slide reveals USB 80G is targeted to support the existing USB-C ecosystem. The higher bandwidth will be achieved thanks to PAM-3 modulation technology. The technique allows the transmitting of a 3-bit signal.

The third line is actually where it gets technically interesting. ‘The PHY will be based on novel PAM-3 modulation technology’. This is talking about how the 0 and 1s are transmitted – traditionally we talk about NRZ encoding, which just allows for a 0 or a 1 to be transmitted, or a single bit. The natural progression is a scheme allowing two bits to be transferred, and this is called PAM-4 (Pulse Amplitude Modulation), with the 4 being the demarcation for how many different variants two bits could be seen (either as 00, 01, 10, or 11). PAM-4, at the same frequency, thus has 2x the bandwidth of an NRZ connection.

Day 1 with the @intel Israel team in the books. Great views…incredible opp to see @GetThunderbolt innovation …a validation lab tour and time with the team…can’t wait to see what tomorrow brings! pic.twitter.com/GKOddA6TNi

— Gregory M Bryant (@gregorymbryant) August 1, 2021