As I wrote before, Thunderbolt now is essentially a certification program for certain USB4 devices and for PCs, there's no difference currently in practice.
With USB4 version 2.0, the program will be called Thunderbolt 5 but the way I read it, Intel is planning to restrict the certification further on lighter workstations. Read this page
Laptop charging: Thunderbolt™ 4 technology for thin and light notebooks that require up to 100W to charge. Thunderbolt™ 5 technology for laptops that require up to 140W to charge. 140W‒240W is available on some devices.
Seems like a small change, doesn't it? Wrong. This is a very big change which tests the clout of Intel against the will of Lenovo/Dell/HP. Let me explain. For near two decades now, all business laptops charge over 20V. From 2014 to 2019, the USB C specification only allowed up to 100W by using 20V 5A. This didn't faze much the big three and they have their proprietary 20V 6.5A (or so) docks. Lenovo even created such a charger last year when PD 3.1 was already out for some time with the appearance of the ThinkPad Z16 and the Z16 Gen 2 this fall still shipped with that (meanwhile the consumer Legion line switched over with the C135 being proprietary last year and the C140 being PD 3.1 this year). At higher wattages they are using proprietary power plugs and combo cables which allows their customers to dock with plugging a single cable and charge at basically any wattage up to like 230W. This means the incentive for PD 3.1 is not really that big.
Now, in 2019 the USB IF raised the wattage but since the connector didn't change, the amperage needed to stay put and so they raised the voltage. This is the big change. If I am reading correctly and Intel will deny certification unless the manufacturer uses PD 3.1 then the big three needs to augment their laptops and docks to support 28V. But also depending on how strict Intel goes, TB5 certification might require downright abandoning their proprietary means because the USB C specification doesn't allow proprietary charging protocols over the C connector (yes, all your phone chargers which support Qualcomm QC over C are not specs compliant).
Will they care? Macbooks with plain (not Pro/Max) CPUs also shipped as USB4 because they do not conform to TB4 requirements of dual displays and it doesn't seem like this made a dent in sales because we are now three generations in and Apple didn't change the capabilities of their lowest tier CPU. On the PC side, AMD models only ship with USB4 too and who cares?
Does Intel have the clout in 2024 to force laptop manufacturers to the new standard or will they shrug and say they don't need a Thunderbolt 5 sticker on those laptops then? Stay tuned, this will be interesting.
