print spoolers typically consume space in /var/ for the files being printed and then stream them to the device through the output filters. The amount of data in play to render a page is not typically that big. Yes, there are corner cases analogous to a zip bomb which can make the print model explode. No, in practice this isn't very normal: printing is one of the spaces where compression of the data is entirely normal. "please print another row of black, where black is that thing I told you before, do that 2048 times and then come back"

Most network printers don't have that much right? I remember seeing a few 256MB sticks in those old copiers that served a whole buildings.

Huh? I don't have any PDF files larger than 150 MB (2500+ pages long).

It won't be a problem. 512 MB is more than enough. The previous revision had 256 MB (that's a bit tight), and the newer PCB does not have RAM less than 1 GB.

Printing stack supports streaming, either per-band (part of a single page) or per-page. Even 1200 DPI CMYK color page is less than 50 MB.