My parents used to own a LaserJet 4M plus, which had PostScript built in. I played around with it once I figured out the possibilities.

It had all of 2MB memory originally, which was a real bottleneck in its later days. I did add 16MB at some point, to increase its life. From then on, when using PostScript instead of PCL for printing, it was clearly CPU-bound.

I’m still conflicted about them taking it to recycling even though it worked reliably. It was over 20 years old.