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X8DTT-H/-HF/-HIBX/-HIBXF/-HIBQ/-HIBQF User's Manual
Memory Support
The X8DTT-H Series motherboard supports up to 48 GB of Registered ECC or
24 GB of Unbuffered ECC/Non-ECC DDR3 1333 MHz/1066 MHz/800 MHz in 12
DIMMs (with max. 4 GB of Registered ECC and 2 GB of Unbuffered memory per
DIMM slot.).
Note
: memory speed support depends on the type of CPU used on the
motherboard.
DIMM Module Population Confi guration
For memory to work properly, follow the tables below for memory installation:
DIMM Population Table
DIMM
Slots per
Channel
DIMMs
Populated
per Channel
DIMM Type (Reg.=
Registered)
Speeds (in MHz)
Ranks per DIMM
(any combination;
SR=Single Rank,
DR=Dual Rank,
QR=Quad Rank)
2
1
Reg. DDR3 ECC
800,1066,1333
SR or DR
2
1
Reg. DDR3 ECC
800,1066
QR
2
2
Reg. DDR3 ECC
800,1066
Mixing SR, DR
2
2
Reg. DDR3 ECC
800
Mixing SR, DR,QR
Note 1
: Due to OS limitations, some operating systems may not show
more than 4 GB of memory.
Note 2
: Due to memory allocation to system devices, the amount of mem-
ory that remains available for operational use will be reduced when 4 GB
of RAM is used. The reduction in memory availability is disproportional.
Possible System Memory Allocation & Availability
System Device
Size
Physical Memory Available
(4 GB Total System Memory)
Firmware Hub fl ash memory (System BIOS)
1 MB
3.99 GB
Local APIC
4 KB
3.99 GB
Area Reserved for the chipset
2 MB
3.99 GB
I/O APIC (4 Kbytes)
4 KB
3.99 GB
PCI Enumeration Area 1
256 MB
3.76 GB
PCI Express (256 MB)
256 MB
3.51 GB
PCI Enumeration Area 2 (if needed) -Aligned on 256-M
boundary-
512 MB
3.01 GB
VGA Memory
16 MB
2.85 GB
TSEG
1 MB
2.84 GB
Memory available for the OS & other applications
2.84 GB