Introduction; Memory Resources; Addressable Memory - Intel BLKD865GBF Specification

2 Technical Reference
What This Chapter Contains
2.1 Introduction.................................................................................................................59
2.2 Memory Resources ....................................................................................................59
2.3 DMA Channels ...........................................................................................................61
2.4 Fixed I/O Map.............................................................................................................62
2.5 PCI Configuration Space Map ....................................................................................63
2.6 Interrupts ....................................................................................................................65
2.7 PCI Interrupt Routing Map ..........................................................................................66
2.8 Connectors .................................................................................................................68
2.9 Jumper Blocks............................................................................................................83
2.10 Mechanical Considerations.........................................................................................85
2.11 Electrical Considerations ............................................................................................88
2.12 Thermal Considerations..............................................................................................89
2.13 Reliability ....................................................................................................................92
2.14 Environmental ............................................................................................................92

2.1 Introduction

Sections 2.2 - 2.6 contain several standalone tables. Table 19 describes the system memory map,
Table 20 lists the DMA channels, Table 21 shows the I/O map, Table 22 defines the PCI
configuration space map, and Table 24 describes the interrupts. The remaining sections in this
chapter are introduced by text found with their respective section headings.

2.2 Memory Resources

2.2.1 Addressable Memory

The board utilizes 4 GB of addressable system memory. Typically the address space that is
allocated for PCI add-in cards, AGP aperture, BIOS (firmware hub), 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:
Memory-mapped I/O that is dynamically allocated for PCI and AGP cards
AGP aperture
APIC and chipset overhead (approximately 18 MB)
BIOS/firmware hub (approximately 2 MB)
The amount of installed memory that can be used will vary based on add-in cards and BIOS
settings. For example, if the PCI cards are requesting 200 MB of system memory and the AGP
aperture is set to 256 MB in the BIOS Setup program, there will be approximately 3.54 GB of
memory that can be accessed. In addition, the Video Frame Buffer setting in the BIOS Setup
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