looks like I'm settling for DS3615xs 1.02b and DSM 6.1.7
no other combo's work, did try 6.2.3 upgrade from 6.1.7 with the same loader but that of course didn't work, booted and was on the network but it didn't recognize the installed DSM
Since the NIC is intel and the i7 3rd gen in there should be fine with the DS3615xs I'm a bit stuck on what could be going wrong, starting to look at what could be wrong with drivers