What memory protection is available to a BL460c Gen8?

If this question references the BL460c Gen8 BUT still asks for 4 answers then HP has been very slack (as usual) at updating the question…
The BL460c G7 supports 4 memory modes – http://h18004.www1.hp.com/products/quickspecs/13706_div/13706_div.PDF

HOWEVER
The BL460c Gen8 supports only 3 memory modes – http://h18004.www1.hp.com/products/quickspecs/14208_div/14208_div.PDF

Just to be clear that there is a difference between Lockstep and Mirroring – http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00256987/c00256987.pdf – Page 11