Windows 7 memory

Regarding the usage of PAE for the purpose of expanding Address space - This is governed by the version/licence of the version of windows you have. PAE is required for enabling DEP for security purposes, but MSFT do not allow/support it for expanding address space in consumer versions of the OS. The reason why is (ostensibly) driver (in)compatibility.

It is possible to get around it by hacking your OS's licence in order to trick Windows into believing it's a Server, rather than a consumer, version.
Geoff Chappell, Software Analyst - Viewer

Strongly NOT recommended for home/casual users, because of potential driver issues.

fseal said:

Ok, here is the scoop.

ScottEq, you are right... ONLY if the physical memory does NOT sit on top of the video ram. See here: techPowerUp! :: What is AGP Aperture size?

The agp aperature is used to map video ram into physical ram it's true. and more physical ram is used up per process that uses video ram.

BUT

When physical memory is large enough that it actually overlaps the video ram which IS mapped into physical space all the time (On a 32 bit OS with 4 gig of ram installed), then your main memory under that video ram becomes unusable.

So in the case of 4 meg of ram, the first bit of ram that comes off is the 768 meg x 2 of the OP's video card setup. THEN when he runs a game, more memory may be mapped to ram in the process as needed through the AGP aperature.

So in the case of Physical RAM being small enough (say 2 gig) you were correct, but in this case with 4 gig of ram, it was what you said PLUS what I said as far as "missing ram" goes. Playing a game on a machine setup such as the OPs would actually end up using 768x2 PLUS the AGP aperature (maybe, depends on demands of the game) while running, and 768x2MB of ram all the time even with nothing running.

This is old (AGP!?!), and no longer applicable. It was one thing to do that when 512MB video cards were "huge", and anything more than 1GB of system memory was a lot. Quite another when GPUs memory is measured in GB, and typical desktop configurations start at 2GB.

Please refer back to the article I originally linked: For obvious reasons, mapping the entire 1.5GB worth of video ram directly into the address space is not supportable: It has the effect of rendering x86 operating systems unusable because there's no address space left for anything other than hardware.

Scotteq said:

Regarding the usage of PAE for the purpose of expanding Address space - This is governed by the version/licence of the version of windows you have. PAE is required for enabling DEP for security purposes, but MSFT do not allow/support it for expanding address space in consumer versions of the OS. The reason why is (ostensibly) driver (in)compatibility.

It is possible to get around it by hacking your OS's licence in order to trick Windows into believing it's a Server, rather than a consumer, version.
Geoff Chappell, Software Analyst - Viewer

Strongly NOT recommended for home/casual users, because of potential driver issues.

interesting read

Bare Foot Kid said:

This from the article I just posted, an I reading it wrong?

System Support for PAE

PAE is supported only on the following 32-bit versions of Windows running on x86-based systems:

• Windows 7 (32 bit only)
• Windows Server 2008 (32-bit only)
• Windows Vista (32-bit only)
• Windows Server 2003 (32-bit only)
• Windows XP (32-bit only)
• Windows 2000 Datacenter Server
• Windows 2000 Advanced Server

Kid - As above, Microsoft limit the usage of PAE via licencing. It *used* to be available on the desktop in (pre~SP2, I believe) Win XP. Since then, it's only been used for security purposes on teh desktop. Not as a tool for expanding address space.

So, technically PAE *is* active on a 32 bit system. Just not available for increasing address space. To enable it requires the hack I linked above.