I'm no longer running the DB Audioware DB-S De-esser plug-in since I don't run on a PC anymore, but when I did it was on a Hewlett Packard Pavilion dv8000 lap top that had a 3.0 Ghz processor and 2 GB of RAM. De-essing plug-ins aren't the type where you need to have many of them up at a time, but this plug-in doesn't take up much processing power anyway so I think you could run a lot of them at a time if you wanted to. Everyone's system has a different make up, so how well it will react really depends on your personal system.
While maybe not the most realistic sounding de-esser plug-in that I've used before, the DB Audioware DB-S De-esser has an interesting make up that sets it apart from other de-ssing plug-ins. It's easy to use once you get the hang of it, and it really makes it easy to zero in on what you'd like done. It's a better make up than your traditional parameters in my opinion, which usually don't leave space for specific frequency input. I wish that they would update this plug-in, as plug-in technology has come a long way since this plug-in was made. It is still worth looking into at this low price, or at least try out the demo...