Accelsior 4M2: Mac Pro Install Notes

Created on: December 30, 2019
Last updated: April 19, 2022

2019 Mac Pro Installs

Please note that the initial batch of Accelsior 4M2 drives have a heat sink that prevents the device from being properly installed in the 2019 Mac Pro. These models were given a specific part number that begins with OWCSSDACC4M2. Those models which will install normally on a 2019 Mac Pro were given the base part OWCSSDACL4M2 The part number groupings are shown below.

Part Numbers (Mac Pro 2010-2012 only + PC)


Part Numbers (also compatible with 2019 Mac Pro):


2010-2012 Mac Pro Installs

Additionally, certain PCIe install configurations are not recommended or supported. Specifically, when certain double-width GPUs are installed in the bottom x16 slot (default / recommended), and the Accelsior 4M2 is installed in the neighboring x16 slot, either the GPU's shroud or its fans can contact one or more screws (or PCBA components) on the bottom of the Accelsior 4M2, causing potential problems. For this reason the XFX RX 580 cards sold by OWC — such as OWCMP1012R580V — cannot be used in conjunction with the Accelsior 4M2 in the above-noted configuration; the Accelsior 4M2 would have to be installed in one of the x4 slots higher up the logic board, which would result in reduced SSD performance.

The following commonly used double-wide GPUs have also been sold by OWC in the past, have been tested with the Accelsior 4M2 in the above dual x16 configuration, and did not make contact with the fans or other critical card components. If each card is installed properly according to Apple's PCIe card recommendations for these Mac Pro models, these configurations should work.

  • Sapphire Radeon 7950
  • Gigabyte Radeon RX 580 Gaming 8G