In my previous post I’ve described how to enable data compression on IIS 6.0 server. The problem I’ve discovered while analyzing HTTP traffic with Fiddler and YSlow is that somehow IIS does not compresses WebResource.axd files. In ASP.NET websites with extensive use of Ajax this issue reduces site’s performance significantly, because of size and amount of axd files in use. Screenshots below demonstrate results of enabling of IIS standard data compression during my tests( here can be found some explanations...