HTTP compression can provide faster transmission times between the Windows Internet Information Services (IIS) and client browsers that can accept compressed files. There are two compression methods supported by IIS:
Static compression - reduces download times for client requests and reduces bandwidth on the server. Use static compression with files that do not typically change.
Dynamic compression - performs dynamic compression each time a client requests content. We recommend this method for content that is created by an application and therefore changes often, such as Active Server Pages (ASP) or ASP.NET content.