Can anyone explain the purpose of a 32 gig NVMe SSD? I think it's quite an apple thing to install such a stupidly tiny drive into a computer, but on the other hand it doesn't seem right. This can't be a system drive can it? But what else could it be? This is like an impractical, high-speed USB drive that requires disassembly of the computer to remove...
It's for the "Fusion Drive." It was just used as a cache basically. You had a larger, slower drive behind it for capacity, this just held frequently accessed data.
Sounds like intels optane drives
More or less. Fusion Drive was introduced when high capacity SSDs were rather expensive. Although the SSD part had 128 GB iirc. Apple stuck with Fusion Drive BTO options for way too long and also nerfed it to 32 GB as evidenced here.
This. I had one in an iMac a while back.
so it's pretty much like SSHDs nowadays, or like read caching?
Pretty much the same, software solution VS hardware one.
https://en.wikipedia.org/wiki/Hybrid_drive#Types