Your memory is REGISTERED. The board only supports un registered dimms.
Recommend picking from the Tested memory list.
The board supports unbuffered (not registered) DDR2 667/800 ECC or non-ECC DIMMs
operating at 667/800 MT/s.
Only DIMMs tested and qualified by Intel or a designated memory test vendor are
supported on this board. All DIMMs are supported by design, but only fully qualified DIMMs are
supported on the board.
The minimum supported DIMM size is 512 MB. Therefore, the minimum main memory
configuration is 1 x 512 MB or 512 MB. The largest size DIMM supported is 2 GB and as such,
the maximum main memory configuration is 8 GB implemented by 4 x 2 GB DIMMs.
Unbuffered DDR2 667/800 compliant, ECC x8 and Non-ECC x8 or x16 memory DIMMs
ECC single-bit errors (SBE) can be detected and corrected. Multiple-bit errors (MBE)
can only be detected.
The maximum memory capacity is 8 GB via four 2 GB DIMM modules.
The minimum memory capacity is 512 MB via a single 512 MB DIMM module.
Wintec 4GB (2 x 2GB) 240-Pin DDR2 SDRAM ECC Registered DDR2 800 (PC2 6400) Server Memory 2Rx8 W/HS Model 3RST8006R9H-4GK
3.3.2 Memory DIMM Support
Got it. Mystery solved. Thanks.
I'll order memory from the approved (tested) list.