We don't actually know what specific version of AMD CPU is available. Just that one option is Ryzen 5 and the other is Ryzen 7:

"For the AMD Ryzen™ 7040 Series processors, we’ll be sharing more detailed specifications as we get closer to shipment."

Source: https://frame.work/gb/en/blog/framework-laptop-13-with-13th-...

The big question is whether the cooling system in the 13" would be able to handle the HS. Is there any data on Zen 4 laptop chips that has tested the efficiency vs performance considerations on the U vs the HS series?

No, but you can look it up here when there are. There is no better notebook reviewer: https://www.notebookcheck.net/AMD-Ryzen-7-7840HS-Processor-B...

On previous generations: the 4000 series starts to hit a relative performance wall at around 35W. The 5000 series clocked higher and hence gained more moving from 15 to 35 and 35 to 45.

Not sure about the 6000 series, but you can see for yourself: https://www.notebookcheck.net/AMD-Ryzen-7-6800U-Processor-Be...

Another point: you can throttle the 35W HS series to 15W, and get the laptop to run fanless or almost fanless since it is designed to cool a higher TDP.

I think so? Of the 7040 APUs, that seems to be the only Ryzen 7 model announced so far.

Shipping estimate is Q3.

I think Zen4 U-series APUs are expected later this year.

They don’t list the specific AMD Ryzen chips. This is the primary reason I refuse to preorder, I need to know exactly what I’m ordering before I do.

I just pre-ordered as well, been eyeing off a Framework for at least a year.