PDFcreator strange output file size differences

I've upgraded from pdfcreator 2.2.2 (running on Windows XP) to 3.3.2 (running on Windows 10). I'm seeing huge differences in PDF file sizes created bty pdfcreator which I find puzzling.

For example:

Input file: ASCII text file, 659 KB, printed from a notepad-like editor, with no revision data or edit backups, etc. In other words, just a simple/plain text file.

Output files:
PDFCreator 2.2.2 output file = 342 KB
PDFCreator 3.3.2 output file = 897 KB

The 3.3.2 version is almost 2.6 times bigger! The two PDF files appear to be identical when viewed in a PDF viewer. So what is all the extra information being stored?

And is it possible to strip it?

As a footnote, as noted in another thread (" 3.3.2 slow print bug?"), 3.3.2 is also drastically slower than 2.2.2