Depending on how many users are connecting to Tableau Server (and therefore our metadata database - postgres.exe) and how many Processes-per-Server have been configured, this could be about right. You'll see multiple tabspawn.exe processes, as they monitor other services. You'll also see "a few" to "very many" postgres.exe processes depending on how many connections are currently in play against the PostgresSQL database that stores information for us. You'll also see one or more of the following: backgrounder.exe, tdserver64.exe, vizqlserver.exe, wgserver.exe, dataserver.exe.
What process are you seeing the "most" of? I'd guess either tabspawn or postrgres...
It's was a test licence and expired ... I can't get the process list now :/
But I was alone to use Tableau ! That why I still amazed to saw so many process.