Microsoft has intentionally crippled IIS in XP to keep people from using it as a web server platform. It defaults to handling only two simultaneous incoming requests. Is there any way to tweak this without serious system file abuse? If so, is there an easy way to test that the change was successful?
I found a suggestion from Tess Ferrandez's debugging blog about some registry settings but all the tests I run after-the-fact seem to indicate nothing has changed (even after an IIS reset and, ultimately, a system restart). In the case of her ASP.NET debugging labs, there is a test page that does a five-second sleep and logs the start and completion of the request but multiple requests to that page on this test system all start five seconds after each other instead of starting around the same time and simply taking five seconds longer from start to completion.
Here is a post by Jeff Atwood on how you can increase the limit to 10 or 40 connections. One way to possibly test would be to use a load tester like Microsoft Application Center Test that comes with Visual Studio 2003 or the Microsoft Application Stress Tool that you can download. This tools will allow you to simulate multiple users hitting your site. I would test it it before you make the change and after to see if it makes a difference.