Intel Desktop Board D945GRW BOXD945GRWLK User Manual
Product codes
BOXD945GRWLK
45
2 Technical
Reference
What This Chapter Contains
2.1 Memory Resources
2.1.1 Addressable
Memory
The board utilizes 4 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), and chipset overhead resides above the top of DRAM (total system memory). On a system
that has 4 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:
allocated for PCI Conventional bus add-in cards, PCI Express configuration space, BIOS (SPI
Flash), and chipset overhead resides above the top of DRAM (total system memory). On a system
that has 4 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 (2 MB)
• Local APIC (19 MB)
• Digital Media Interface (40 MB)
• Front side bus interrupts (17 MB)
• PCI Express configuration space (256 MB)
• MCH base address registers, internal graphics ranges, PCI Express ports (up to 512 MB)
• Memory-mapped I/O that is dynamically allocated for PCI Conventional and PCI Express
• Digital Media Interface (40 MB)
• Front side bus interrupts (17 MB)
• PCI Express configuration space (256 MB)
• MCH base address registers, internal graphics ranges, PCI Express ports (up to 512 MB)
• Memory-mapped I/O that is dynamically allocated for PCI Conventional and PCI Express
add-in cards
The amount of installed memory that can be used will vary based on add-in cards and BIOS
settings. Figure 14 shows a schematic of the system memory map. All installed system memory
can be used when there is no overlap of system addresses.
settings. Figure 14 shows a schematic of the system memory map. All installed system memory
can be used when there is no overlap of system addresses.