DG45FC Datasheet, PDF (39/88 Pages) Intel Corporation – Technical Product Specification

2 Technical Reference
2.1 Memory Map
2.1.1 Addressable Memory
The board utilizes 4 GB of addressable system memory. Typically the address space
that is allocated for 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 (32 Mbits)
• Local APIC (19 MB)
• Direct Media Interface (40 MB)
• Front side bus interrupts (17 MB)
• PCI Express configuration space (256 MB)
• GMCH base address registers, internal graphics ranges, PCI Express ports (up to
512 MB)
• Memory-mapped I/O that is dynamically allocated for PCI Express add-in cards
• Base graphics memory support (1 MB or 8 MB)
• Intel^® Management Engine Interface (Intel^® MEI) single channel (8 MB) or dual
channel (16 MB)
39