I do not believe it can use none ECC memory.
See pages 3 and 85.
"The workstation dual in-line memory modules (DIMMs) are based on DDR3 1333MHz technology, and
are error checking and correcting (ECC)-protected"
"Use only industry-standard ECC unbuffered DIMMS"
http://jp.ext.hp.com/lib/doc/manual/workstation/hp_workstation/504630_001.pdf