DX58SO datasheet(39/88 Pages) INTEL

39 / 88 page

Technical Reference

2.1

Memory Resources

2.1.1

Addressable Memory

The board utilizes 16 GB of addressable system memory. Typically the address space

that is allocated for PCI Conventional bus add-in cards, PCI Express configuration

space, BIOS (SPI Flash device), and chipset overhead resides above the top of DRAM

(total system memory). On a system that has 16 GB of system memory installed, it is

not possible to use all of the installed memory due to system address space being

allocated for other system critical functions. These functions include the following:

•

BIOS/SPI Flash device (16 Mbit)

•

Local APIC (19 MB)

•

Direct Media Interface (40 MB)

•

Front side bus interrupts (17 MB)

•

PCI Express configuration space (256 MB)

•

IOH base address registers PCI Express ports (up to 256 MB)

•

Memory-mapped I/O that is dynamically allocated for PCI Conventional and PCI

Express add-in cards (256 MB)

The board provides the capability to reclaim the physical memory overlapped by the

memory mapped I/O logical address space. The board remaps physical memory from

the top of usable DRAM boundary to the 4 GB boundary to an equivalent sized logical

address range located just above the 4 GB boundary. Figure 9 shows a schematic of

the system memory map. All installed system memory can be used when there is no

overlap of system addresses.

DX58SO データシート(PDF) 39 Page - Intel Corporation