First of all the correct part # is M393B4G70BM0-YH9 & these have been tested by myself working on a dual cMPI've just received one stick of Samsung M393B4G70BMO-YH9 32GB 4Rx4 PC3L-10600R, it doesn't boot with a single X5650 (High Sierra 10.13.6, firmware 140.0.0.0.0).
I have a single 2010 5,1 in my office, i can check/test 1 module (i have the same modules as you) to see if it works & report back to you with regards to issues of non-compatibility using a single processor cMP