Intel D915GAG Product Specification - Page 56

Detailed System Memory Address Map

Page 56 highlights

Intel Desktop Board D915GAV/D915GAG Technical Product Specification • 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 17 shows a schematic of the system memory map. All installed system memory can be used when there is no overlap of system addresses. 4 GB Top of System Address Space FLASH APIC Reserved ~20 MB PCI Memory Range contains PCI, chipsets, Direct Media Interface (DMI), and ICH ranges (approximately 750 MB) DRAM Range DOS Compatibility Memory Top of usable DRAM (memory visible to the operating system) 1 MB 640 KB 0 MB 0FFFFFH 0F0000H 0EFFFFH 0E0000H 0DFFFFH 0C0000H 0BFFFFH 0A0000H 09FFFFH 00000H Upper BIOS area (64 KB) Lower BIOS area (64 KB; 16 KB x 4) Add-in Card BIOS and Buffer area (128 KB; 16 KB x 8) Standard PCI/ ISA Video Memory (SMM Memory) 128 KB DOS area (640 KB) 1 MB 960 KB 896 KB 768 KB 640 KB 0 KB OM17140 Figure 17. Detailed System Memory Address Map 56

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Intel Desktop Board D915GAV/D915GAG Technical Product Specification
56
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 17 shows a schematic of the system memory map.
All installed system memory
can be used when there is no overlap of system addresses.
Upper BIOS
area (64 KB)
Lower BIOS
area
(64 KB;
16 KB x 4)
Add-in Card
BIOS and
Buffer area
(128 KB;
16 KB x 8)
Standard PCI/
ISA Video
Memory (SMM
Memory)
128 KB
DOS area
(640
KB)
1 MB
960 KB
896 KB
768 KB
640 KB
0 KB
0FFFFFH
0F0000H
0EFFFFH
0E0000H
0DFFFFH
0C0000H
0BFFFFH
0A0000H
09FFFFH
00000H
FLASH
APIC
Reserved
0 MB
640 KB
1 MB
Top of usable
DRAM (memory
visible to the
operating
system)
PCI Memory Range -
contains PCI, chipsets,
Direct Media Interface
(DMI), and ICH ranges
(approximately 750 MB)
DOS
Compatibility
Memory
DRAM
Range
OM17140
~20 MB
4 GB
Top of System Address Space
Figure 17.
Detailed System Memory Address Map