Max requests/sec of 400 per client in IIS 7

I am seeing a strange behavior with IIS 7.

I am running IIS 7 on Windows 2008 server standard edition SP1

I have a console app client which sends Http Get requests to a Website hosted on IIS 7

The max number of requests/sec i achieve is 400 with each client. i.e. if I have 2 console app clients running then I get a max of 800 requests/sec

If I run the same console app client against a website hosted in IIS 6 then I get close to 5000 requests/sec per client.

Can some one help in explaining how I can achieve 5000/requests/sec per client on IIS 7.

 Your help will be grately appreciated .

 Thanks