My .Net 4 web app was running on windows server 2003 38 bit.
I've just upgraded to a new server with windows server 2008 64 bit.
I still got both servers running the same web app,
On windows server 2003 the app takes 55k RAM
And on windows server 2008 it takes 285K RAM
Same application, didn't change a thing and there are still no users at the new server.
What am I missing? Can the same application take a lot more memory on windows 2008?
You might say "Windows Server takes 5 times as much RAM. OMG!!!!"
I prefer to say "Windows Server just uses 200K more initial space. Who cares?"
The important thing is to see how the application scales under load.
I suspect the difference with several concurrent users will be relatively small. I'm guessing that, ultimately, Server 2008 will scale better.
But the only way to be sure is to test it.