User`s manual
Chapter 2: Installation
2-13
Note: Due to memory allocation to system devices, the amount of memory that
remains available for operational use will be reduced when 4 GB of RAM is
used. The reduction in memory availability is disproportional.
For Microsoft Windows users: Microsoft implemented a design change in Win-
dows XP with Service Pack 2 (SP2) and Windows Vista. This change is specic
to the Physical Address Extension (PAE) mode behavior which improves driver
compatibility. For more information, please read the following article at Microsoft’s
Knowledge Base website at: http://support.microsoft.com/kb/888137.
Possible System Memory Allocation & Availability
System Device Size Physical Memory
Remaining (-Available)
(4 GB Total System Memory)
Firmware Hub ash memory (System
BIOS)
1 MB 3.99
Local APIC 4 KB 3.99
Area Reserved for the chipset 2 MB 3.99
I/O APIC (4 Kbytes) 4 KB 3.99
PCI Enumeration Area 1 256 MB 3.76
PCI Express (256 MB) 256 MB 3.51
PCI Enumeration Area 2 (if needed)
-Aligned on 256-MB boundary-
512 MB 3.01
VGA Memory 16 MB 2.85
TSEG 1 MB 2.84
Memory available to OS and other ap-
plications
2.84