Datasheet

Intel® S5000 Server Board Family Datasheet System BIOS

Revision 1.3

Intel order number D38960-006

 If the Display Logo is disabled, the BIOS displays the total system memory on the

diagnostic screen at the end of POST. This total is the same as the amount described by

the first bullet, above.

 The BIOS provides the total amount of memory in the system by supporting the EFI Boot

Service function GetMemoryMap().

 The BIOS provides the total amount of memory in the system by supporting the INT 15h,

E820h function. See the Advanced Configuration and Power Interface Specification,

Revision 2.0 for details.

Note: Memory between 4 GB and 4 GB minus 1.5 GB is not accessible for use by the operating

system and may be lost to the user. This area is reserved for BIOS, APIC configuration space,

and virtual video memory space. See section 3.3.3.1. Memory will also be reserved for PCI /

PCI Express* / PCI Express resources. This means that if 4 GB of memory is installed, 2.5 GB

or less of this memory is usable. The chipset allows remapping unused memory above the 4 GB

address. To take advantage of this, turn on Physical Address Extensions (PAE) in your

operating system.

3.3.3.1 Memory Reservation for Memory-mapped Functions

A region of size 0.25 GB of memory below 4 GB is always reserved for mapping chipset,

processor and BIOS (flash) spaces as memory-mapped I/O regions. This region will appear as

a loss of memory to the operating system. In addition to this loss, the BIOS creates another

reserved region for memory-mapped PCI Express* functions, including a standard 0.25 GB of

standard PC Express configuration space. This memory is reclaimed by the operating system if

PAE is turned on in the operating system.

3.3.3.2 High-Memory Reclaim

When 4 GB or more of physical memory is installed, the reserved memory is lost. However, the

Intel

5000 Series Chipset provides a feature called high-memory reclaim that allows the BIOS

and the operating system to remap the lost physical memory into system memory above 4 GB.

The system memory is the memory that can be seen by the processor.

The BIOS will always enable high-memory reclaim if it discovers installed physical memory

equal to or greater than 4 GB. For the operating system, the reclaimed memory is recoverable

only when it supports and enables the PAE feature in the processor. Most operating systems

support this feature. See the relevant operating system manuals for operating system support in

your environment.

3.3.3.3 Memory Interleaving

In general, to optimize memory accesses, the BIOS will enable Branch Interleaving, which

allows the chipset to interleave data for successive cache-lines between the autonomous

branches. Branch Interleaving is not possible on some platforms, since these do not have

Branch 1 enabled.

Additionally, the Intel

5000 sequence MCH also provides interleaving across logical memory

devices called ranks. A pair of single-ranked lock-stepped FBDIMMs constitutes a memory rank.

Interleaving effected between ranks allows the chipset to interleave cache-line data between