Asus Crosshair II Formula - Manual (Page 41)

ASUS Crosshair II Formula 2-15
2.4.2 Memory configurations
You may install 256 MB, 512 MB, 1 GB, and 2 GB unbuffered ECC/non-ECC
DDR2 DIMMs into the DIMM sockets.
Recommended Memory Configurations
• 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 GB 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/Vista 32-bit operation system which
does not support Physical Address Extension (PAE).
• If you install Windows ® XP/Vista 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.
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.
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
64-bit
Windows ® XP Professional x64 Edition
Windows ® Vista x64 Edition