Intel BLKDG43NB Product Specification - Page 39

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 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 (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 Conventional and PCI Express add-in cards • Intel® Management Engine (Intel® ME) support (6 MB) • Base graphics memory support (1 MB or 8 MB) NOTE System resources and hardware (such as PCI and PCI Express*) require physical memory address locations that can reduce available addressable system memory. This could result in a reduction of as much as 1 GB or more of physical addressable memory being available to the operating system and applications, depending on the system configuration and operating system. 39