It turns out this issue comes down to mixing 30440 with 30330. Since the Apple factory is 330 I decided to return my 440's and go all 330. The speed difference is supposed to be "insignificant".
Removing all the 330's and running all 440 resolved my issue as well.
Side note: One of the "Matched Pairs" Other World Computing sent me was actually one of each (one 330 and one 440), they also insist that the ram was tested before being shipped. What "tested" actually meant seemed somewhat unclear.