By default, Edit and Continue loads and processes precompiled headers in the background to speed up processing of code changes. Loading precompiled headers requires allocation of physical memory, which can be a problem if you are compiling on a machine with limited RAM. Under Windows NT or Windows 2000, you can determine if this might be a problem by using the Windows NT Task Manager to determine the amount of available physical memory while you are debugging. If this amount is greater than the size of your precompiled headers, Edit and Continue should have no problem. If the amount is less than the size of your precompiled headers, you can prevent Edit and Continue from loading precompiled headers in the background.
To disable background loading of precompiled headers for Edit and Continue