Can PostGreSQL slow down a Windows PC much?

Our software will be using PostGreSQL as a database. Now I was wondering, if
the database is installed on lets say an entry level Celeron, with 256MB of
Ram, will it slow down the PC at all?

I'm not taking any queries into account here, just generally, does
installing the database slow down ones PC a bit? Unfortunately I don't have
access to such an entry-level PC, so I can't test it.

Thanks