In For IIS 7.0 / IIS 7.5 the worker process (w3wp.exe) taking too much memory, then you can try the below steps.
>>From Windows Control Panel / Administrative tools, open Server Manager
>>Expand Roles and select Web Server (IIS)
>> On the right pane, for the "Roles Services" section, click "Add Role Services"
>> Under "Application Development", check "ASP" if this is not already checked
>> Once this module is installed, close Server Manager and open Internet Information Services (IIS) Manager (7.x)
>> In the left hierarchy, select the root of the treeview (machine name)
>> On the right pane, under "IIS" section, double-click the "ASP" icon
>> A list of properties is displayed. Expand "Caching Properties"
>> Change "Maximum Memory Cached Files" from 500 to 5
>> Restart IIS
That's it !