Specifically the 6-Core model because that's what I own. According to this table from OWC: https://eshop.macsales.com/shop/mem...1.204008400.1181529146.1468163367#1333-memory 48GB (3x16GB) is the maximum ram I can have. But I saw a video on YouTube from someone who has the same Mac Pro 5,1 as I do and they have 64GB (4x16GB) so I emailed OWC about this and what they had to say, "64GB would only be possible using 8x8GB or 4x16GB. Your model has 4 slots and could physically fit 4x16GB but that is not stable, the ram processor cannot handle that amount. Per extensive OWC testing only the 3x16GB is stable." I also emailed the person on YouTube and they said 64GB worked fine so I'm curious to know how much ram you have and what is your maximum? Have you found that the ram processor can handle over 48GB if you have so?