One of the performance benefits of the x64 platform is that it increases virtual address space, making more memory available. We recommend that you configure IIS to use a 32-bit worker processes on 64-bit Windows. Not only its compatibility better than the native 64-bit, performance and memory consumption are also better.
Set the Web server to enable this globally so that you do not need to set it for each application pool. Unlike previous versions of IIS, you can now configure specific worker processes to run in 32-bit or 64-bit mode independently of each other on the same server.
To configure 32-bit mode for the server
Open a command prompt and run the following:
%windir%\system32\inetsrv\appcmd set config -section:applicationPools -applicationPoolDefaults.enable32BitAppOnWin64:true
Note: This setting applies only to 64-bit servers.