What are your RAID cache settings?
Have you tweaked the initiator advanced properties to match DSS V7?
===
QueuedCommands=8
DataDigest=None
MaxOutstandingR2T=32
InitialR2T=No
FirstBurstLength=65536
MaxRecvDataSegmentLength=1048576
HeaderDigest=None
MaxXmitDataSegmentLength=1048576
ImmediateData=Yes
MaxBurstLength=1048576