Does a webapplication run faster when Maximum Worker Processes is more than one?

By increasing the Maximum Worker Processes over 1 you're creating a Web Garden. So the short answer is: likely no... unless:

To quote Chris Adams an ex IIS PM's article I have flowers... should I get a Web Garden?:

Web gardens was designed for one single reason – Offering applications that are not CPU-bound but execute long running requests the ability to scale and not use up all threads available in the worker process.
The examples might be things like -
Applications that make long running database requests (e.g. high computational database transaction)
Applications that have threads occupied by long-running synchronous and network intensive transactions
The question that you must ask yourself -
What is the current CPU usage of the server?
What is the application’s threads executing and what type of requests are they?
Based on the criteria above, you should understand better when to use Web Gardens. Web Gardens, in the metabase, equals the MaxProcesses metabase property if you are not using the User Interface to configure this feature.
cscript adsutil.vbs set w3svc/apppools/defaultapppool/maxprocesses 4
I hope that I get some mileage out of having this blog and more importantly I hope it helps you understand this better…

You may want to look at "What is Web Garden?" from Deploying ASP.NET Websites on IIS 7.0 [codeproject.com] which says:

By default each Application Pool runs with a Single Worker Process (W3Wp.exe). We can assign multiple Worker Processes With a Single Application Pool. An Application Pool with multiple Worker process is called "Web Gardens". Many worker processes with the same Application Pool can sometimes provide better throughput performance and application response time. And each worker process should have their own Thread and Own Memory space.