Here is a review I appreciated that tore it down and explained the heatsink from JeffGeerling.com

Cut and paste from his review with the full link below:  "

One thing you might notice in the Pi 400's specs is a new, higher default clock speed than you get with the year-old Pi 4 model B.

It's clocked at 1.8 GHz out of the box, while the Pi 4 model B is clocked at 1.5 GHz.

In some quick Phoronix benchmarks, the Pi 400 performed about 18% faster than the Pi 4 model B at the higher clock speed... which is expected, since that's the same ratio as the increase in megahertz.

But how is this higher clock possible? Well, not only is the massive heatsink helpful here—the Pi 400 didn't overheat even when I was running it with an overclock to 2.147 GHz, the maximum it allows currently—but the actual BCM2711 chip is different in this model:

"

https://www.jeffgeerling.com/blog/2020/raspberry-pi-400-teardown-and-review

I so want to get my hands on one of these and test it out!  This screams customize a Cyberdeck to me!

Hi David,

I saw in a YouTube video yesterday that it's a large (keyboard-sized) thin stamped sheet of aluminium, taped to the BCM.. chip and overall screwed onto the plastic chassis (industrial products would do it very much differently but that's a different use-case).

I think even if there was zero heatsinking it will self-protect itself if it needs to by reducing speed. I have a couple of Pi 4 boards that run permanently with zero heatsinking, they seem fine in an enclosure with some air vents, as you say nice and warm! but I don't do any heavy processing.

I am curious to see a teardown of this device to see how is the thermal management solved. RPi 4 can get very hot. On the other hand, it is very comfortable to write on a warn keyboard during the cold season

Very cool : )

It has a very retro feel (in a nice way) and definitely simplifies things to get going.

Plus it is barely more expensive than a regular Pi + heatsink + case, and a much tidier-looking solution, so almost a no-brainer to purchase this over the regular Pi, even if the keyboard portion isn't frequently used (after all, people do the same with laptops.. attach their own external keyboards and monitors).

I'm guessing the 40-way connector is back-to-front so that a ribbon cable will correct it for any boards to plug in (in which case hopefully the bundled book etc might mention it, otherwise people might start wiring in stuff directly to the port, assuming it's numbered exactly like the earlier Pi boards).

I noticed that it was already out of stock.

DAB

very interesting, this reminds me of my childhood, with Apple II, Sinclair ZX80/81, Spectrum, Tandy TRS80, Comodore VIC20, C64 etc. etc.

All computers in a keyboard housing, with IO headers at the back, and a connection to a television (NTSC/PAL).

nice!

I definitely want one!

It's a fine thing.

But the keyboard... hm....

At school I learned to write on the typewriter, oh yes, in English and German.

I write pretty fast now, but here ... ???  Where are !!!! the character ??? ----

"They seem to have been rolled here."

https://en.wikipedia.org/wiki/AZERTY

https://en.wikipedia.org/wiki/QWERTY

Do you really think I'm going back to school? 

What will the Raspberry PI guys invent next ? A rocket ship controlled by a Raspberry PI ?

It's a wonderful idea - not new, but a wonderful idea. I'll get one when the keyboard layout will be available in PT Qwerty .