Edit: Snipped, misread last sentence as a question
Quote: Originally Posted by sygnus21
Quote: Originally Posted by murmatron
The memory is not hardware reserved. 32-bit Windows 7 deliberately prevents you from using it even if PAE is enabled.
So, it is therefore... hardware preserved. The fact that you can use a 3rd party program to get around it doesn't negate the fact that "Windows 7 deliberately prevents you from using it even if PAE is enabled
And yes WHS, it is a address space thing.
The RAM between 3.25GB and 4GB is absolutely not hardware reserved; it's remapped (as Corazon stated) to above 4GB so that the devices in the machine can be accessed through memory-mapped I/O in the region below 4GB. The remapping is necessary because the PCI-Express bus still only has 32bit address lines and can't address memory above 4GB. This is true even in 64bit Windows, Linux or whatever - it's not done by the operating system.
By contrast, every processor since the Pentium-I-can't-remember-which-one-exactly has been capable of 36bit PAE addressing (that's 64GB)
The claim that allowing PAE addressing in Windows causes (or caused at some point in the past) problems with some drivers may well be true for drivers that are not written following the Windows DDK specification, with the 'gotcha' being that realistically, there's no way to tell in advance of them crashing your system. For that reason I more-or-less accept Microsoft's stated rationale for hobbling PAE on desktop Windows since XP-SP3, but the fact remains that there exists a way to use this memory in a way that makes badly written drivers irrelevant, so I often feel the need to point this out.
It's interesting to note that Gavotte Ramdisk is based on a sample ramdisk program provided by Microsoft in the Windows DDK a long time ago.