Asus P5B VM P5B-VM English Edition User's Manual - Page 31

• You may install varying memory sizes in Channel A and Channel B. The system maps the total size of the lower-sized channel for the dual-channel configuration. Any excess memory from the higher-sized channel is then mapped for single-channel operation. • Always install DIMMs with the same CAS latency. For optimum compatibility, it is recommended that you obtain memory modules from the same vendor. • If you install four 1 or 2GB memory modules, the system may only recognize less than 3GB because the address space is reserved for other critical functions. This limitation appears on Windows® XP 32-bit operation system which does not support Physical Address Extension (PAE). • If you install Windows® XP 32-bit operation system, a total memory of less than 3GB is recommended. • This motherboard does not support memory modules made up of 128 Mb chips or double sided x16 memory modules. Notes on memory limitations • Due to chipset limitation, this motherboard can only support up to 8 GB on the operating systems listed below. You may install a maximum of 2 GB DIMMs on each slot, but only DDR2-533 and DDR2-667 2 GB density modules are available for this configuration. 32-bit Windows® 2000 Advanced Server 64-bit Windows® XP Professional x64 Edition • Some old-version DDR2-800/667 DIMMs may not match Intel®'s On‑Die‑Termination (ODT) requirement and will automatically downgrade to run at DDR2-533. 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. • Due to chipset limitation, DDR2-667 with CL=3 will be downgraded to run at DDR2-533 by default setting. If you want to operate with lower latency, adjust the memory timing manually. There will be 8MB reduction in total memory when enabling ASUS Thermostat function under Single Channel mode, and 16MB reduction under Dual Channel Mode. • The total memory may has 8MB reduction under Single Channel mode, and 16MB reduction under Dual Channel mode because the address space is reserved for Intel® Quiet System Technology. ASUS P5B-VM 1-19