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Addressing Memory with 4-GB Configurations
If you use optional memory riser boards and eight,
Certain components within the computer require address space in the
•System ROM
•APIC(s)
•Integrated PCI devices, such as the network adapter, SCSI controller, and IEEE 1394 controller
•PCI and AGP expansion cards
•The AGP Aperture size specified in system setup
At system
In other words, the BIOS dynamically calculates the amount of reserved address space required. It then subtracts the reserved address space from
4 GB to determine the amount of usable address space:
•If the total installed computer memory is less than the usable address space, all installed computer memory is available for use by the OS.
•If the total installed computer memory is equal to or greater than the usable address space, a small portion of installed computer memory is not available for use by the OS.
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