Really? Doesn't Windows enable PAE automatically when the system has more than 4GB?
On consumer versions of Windows, PAE not used for memory. DEP
(Data Execution Prevention) and a couple other tricks, yes. But not for memory.
The way it works for Memory is it allows an added table the OS can use to add the “same” address in more than one place. Think of this as adding a "street name" to your "address". 1234567890 on table A is not the same as 1234567890 on table B. The limitation is that this *must* be provided for in your programs and drivers in order to work. If your mailman only looks at the '1234567890' but never looks at the street name, then he can and will sometimes deliver a letter to the wrong place. The same thing is true of PAE - If/when then individual program haven’t been coded to look in multiple tables for the needed memory locations in addition to the numerical addresses, messages can and will often go to the wrong place. In Windows, this is a called a “memory access violation”, and results in a blue screen. Additionally, individual programs under PAE can still only use up to 4 GB. Kernels and drivers can be made aware of PAE, but they can still only use 4 GB ranges at a time.
In short: PAE is not that great. In a server environment the number/version/type of programs and drivers can be tightly controlled, so this works and so this functionality is available on server versions of 32 bit Windows (NT, 2003, 2006, etc). In a consumer environment, this is not true at all.
Bottom line for ‘regular’ users: If you want to use 4 GB of RAM or more, then you should buy 64-bit hardware and use a 64-bit OS.
{Apologies for the Cut/Paste, but this topic comes up with a high degree of regularity on another forum I participate in. Enough so, that I have a number of pre-written answers.}
