IIS 7.5 strange behaviour


We recently migrated from IIS6 to IIS7 and we have a strange
situation happening. All our applications are working fine, but I have
this page code in ASP that used AJAX who will display in 15 seconds
with IIS6, now takes about 1 min. 30 sec. to show with IIS7.

I ran a trace on my IIS 7 server and I was surprised to see that the
page took indeed 15 seconds to execute and about 1m 30s to show up on
a browser.

I've create an application pool in classic mode without any managed
code. I've played with many of the parameters like the limits
properties in the module ASP at the server level, the website level
and the application level, didn't do nothing. I've used compressions,
checks permissions, nothing.

Does someone has a clue of what is going on with this server?

Thank you very much for all your comments