/3GB /PAE and AWE blurb what is it you hear within your environment?

You might have come across a situation to have a better understanding on what /3GB or /PAE switch means that are referred in documentations and forums you go on. I will try my best to give you the notes what I have understood so far in this regard.

From the available documentation on Technet & MSDN it is pretty informative that :

The /3GB switch allocates 3 GB of virtual address space to an application that uses IMAGE_FILE_LARGE_ADDRESS_AWARE in the process header. This switch allows applications to address 1 GB of additional virtual address space above 2 GB. The virtual address space of processes and applications is still limited to 2 GB, unless the /3GB switch is used in the Boot.ini file.

To be more specific this /3GB and AWE (Address Windowing Extensions ) is introduced from the operating systems based on Windows NT technologies have always provided applications with a sensible 32-bit virtual address space that describes 4 GB of virtual memory. The address space is usually split so that 2 GB of address space is directly accessible to the application and the other 2 GB is only accessible to the Windows executive software. In this cycle Windows 2000 Advanced Server and Windows NT4 Enterprise edition are first ones to have such features introduced, which are now very common in Windows 2003 and upcoming operating system versions.

Coming to PAE (Physical Address Extension) is a proprietary (Intel) based memory extension that supports upto 64 GB for physical memory on a 32bit platform. This extension helps the processors to expand the number of bits that can be used to address physical memory from 32 bits to 36 bits through support in the host operating system for applications using the AWE features.

Further to this blurb I strongly recommend to read Chad Boyd's  BlogPost on the subject that has a detailed and excellent information and MSDN Setup-3gb_Switch link too.