Memory size information does not appear correctly in System Properties

 

Memory size information does not appear correctly in System Properties. PC is IBM ThinkCentre 8215-D6U w/ Windows XP Pro and Service Pack 2(5.1.2600 build).  PC specs state: "If 4GB of physical memory is installed approximately 3GB will be useable by the operating system. This is due to limitations from the address mapping of PCI busses and other system devices."

 

I read this about PAE:

Physical Address Extension (PAE) is the feature of the Intel 32 bit architecture that expands the physical memory (RAM) address to 36 bits (see KB articles 268363 and 261988).  PAE does not change the size of the virtual address space, which remains at 4 GB, just the amount of actual RAM that can be addressed by the processor. The translation between the 32 bit virtual memory address used by the code running in a process and the 36 bit RAM address is handled automatically and transpar ...