Asus P5KPL-AM EPU User Manual - Page 23

1.7.2 Memory configurations You may install 512MB, 1GB, and 2GB unbuffered non‑ECC DDR2 DIMMs into the DIMM sockets. • When using only one DDR2 DIMM, start installing it from DIMM_A1 or DIMM_B1 for better overclocking capability. • For dual-channel configuration, install two identical DIMMs in DIMM_A1 and DIMM_B1. • 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 do any of the following: - Use a maximum of 3GB system memory if you are using a 32-bit Windows® OS. - Install a 64-bit Windows® OS when you want to install 4GB or more memory on the motherboard. • This motherboard does not support DIMMs made up of 256 megabits (Mb) or less. • This motherboard supports up to 4 GB on Windows® XP Professional x64 and Windows® Vista x64 editions. You may install a maximum of 2GB DIMMs on each slot. • The default memory operation frequency is dependent on its Serial Presence Detect (SPD), which is the standard way of accessing information from a memory module. Under the default state, some memory modules for overclocking may operate at a lower frequency than the vendor-marked value. • For system stability, use a more efficient cooling system to support a full memory load (2 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. ASUS P5KPL-AM EPU 1-13