5 Things to Know About RAM for the 2019 Mac Pro

You must use ECC memory The 2019 Mac Pro only works with ECC RAM. The machine will not boot without it, so you are not choosing between ECC and non-ECC.

Use RDIMMs or LRDIMMs, not unbuffered ECC The Mac Pro requires registered ECC (RDIMMs) or load-reduced DIMMs. Cheaper unbuffered ECC sticks meant for consumer boards will not work.

Stick to vendors that guarantee compatibility Apple’s firmware can reject third-party RAM, even from reputable brands. Buy from OWC, Crucial, or other vendors that explicitly list Mac Pro 2019 compatibility.

Do not mix capacities or speeds across channels Mixing different capacities or speeds forces the system to run at the slowest common denominator. This applies to any workstation, not just Apple.

The Mac Pro only shipped with Intel Xeon W processors All 2019 Mac Pros use Xeon W chips. There is no option for other CPU types, so your RAM choice must match that platform.