That's great information. I had no idea Chromebook prototypes started as early as N455, but since you're skilled with Arch, I'll recommend two distros(one isn't really a distro, but a toolkit) for your cr-48 : Tiny Core Linux, and NanoLinux. The latter is built on TCL and a distro was released on Sourcefourge around 2015- no releases since..

One could really optimize an N450 using a very light package manager over TCL, although it's possible you already have something like that on Arch. With TCL, more assembly is required.

I also used SliTaz on an EeePc 701 back in the day, and I used it more because it had out of the box wifi support. https://slitaz.org/en/ At just 30MB, quite unbeatable. The OS gets some updates still, but it's a smaller project and probably less known. I suppose you could also try Damn Small Linux 2024: https://www.damnsmalllinux.org/2024-download.html

Edit: I added some notes on my tests here, and found the codec that is supported on the N450: MPEG-2: https://github.com/hatonthecat/linux_distro_tests#exegnulinu...

https://youtu.be/jMUeePXx8Ek?is=d938n8NobjBjoOlc

What makes the N450 tolerable over the Celeron 630 and even N270 is that it has hyperthreading, so it's like a dual core computer in some cases, but technically single core. It's not as fast as the AMD C-50 (with better GPU and out of order instructions, but fast enough for very light weight applications.)

Admittedly, I don't use it as a daily driver and only test it when there's a lightweight distro I want to check. Knowing i915 supports Wayland makes me want to test it again

(The AMD FX series did something like this, saying their FX 8350 was 8 cores, but it was really 2-4 physical cores and 8 logical cores): https://www.reddit.com/r/Amd/comments/ngnwp7/did_the_amd_fx_... (I have an FX-8320E, and it's not super slow though-quite fast in fact)