The 8000 series included a new display chip which drove an 80×25 character screen, but this resulted in a number of software incompatibilities with programs designed for the 40 column screen, and it appears to have been unpopular as a result. The machine shipped with 32 kB standard as the 8032, but allowed another 64 kB to be added externally. Later the upgrade was installed from the factory, creating the 8096.] Unlike the 40-column models, 8000-series PETs came standard with a 1-channel speaker for sound generation.
Source: Wikipedia, "Commodore PET", available under the CC-BY-SA License.