Asus P5QL/EPU - Manual (Page 22)

1-12 Chapter 1: Product introduction
1.7.2 Memory configurations
You may install 512MB, 1GB, 2GB, and 4GB unbuffered non-ECC DDR2 DIMMs into the
DIMM sockets.
Recommended Memory Configurations
Mode
Sockets
DIMM_A1 DIMM_A2 DIMM_B1 DIMM_B2
Single-Channel
- - Populated -
Populated - - -
Dual-channel.(1) Populated - Populated -
Dual-channel.(2) Populated Populated Populated Populated
• When using only one DDR2 DIMM, start installing it from DIMM_A1 or DIMM_B1 for
better overclocking capability.
• For dual-channel configuration (1), install two identical DIMMs in DIMM_A1 and
DIMM_B1.
• For dual-channel configuration (2), you can:
-
install four identical DIMMs in all four slots; or
- install one identical DIMM pair in DIMM_A1 and DIMM_B1 (yellow slots) and
another identical DIMM pair in DIMM_A2 and DIMM_B2 (black slots).
• Always install DIMMs with the same CAS latency. For optimum compatibility, it is
recommended that you obtain memory modules from the same vendor.
• Due to the memory address limitation on 32-bit Windows OS, when you install 4GB
or more memory on the motherboard, the actual usable memory for the OS can be
about 3GB or less. For effective use of memory, we recommend that you install a 64-bit
Windows OS when having 4GB or more memory installed on the motherboard.
• This motherboard supports up to 16GB on a Windows ® XP Professional x64 and
Windows ® Vista x64 Edition. You may install a maximum of 4GB DIMM on each slot.
• The default memory operation frequency is dependent on its SPD. Under the default
state, some memory modules for overclocking may operate at a lower frequency than
the vendor-marked value. To operate at the vendor-marked or at a higher frequency, see
section 2.4.Ai.Tweaker.menu for manual memory frequency adjustment.
• For system stability, use a more efficient cooling system to support a full memory load (4
DIMMs) or overclocking conditions.
• Some old-version DDR2-800 DIMMs may not match Intel ® ’s On-Die-Termination (ODT)
requirement and will automatically downgrade to run at DDR2-667. If this happens,
contact your memory vendor to check the ODT value.
• Due to chipset limitation, DDR2-800 with CL=4 will be downgraded to run at DDR2-667
by default setting. If you want to operate with lower latency, adjust the memory timing
manually.
• This motherboard does not support DIMMs made up of 256 megabit (Mb) chips or less.