5 Things to Know About Mixing ECC RAM Brands

Mixing brands is fine As long as the specs match, you can mix brands of unbuffered ECC DDR3 or DDR4 without issues.

Match speed and voltage Speed (e.g., 1333MHz or 1600MHz) and voltage (1.35V vs 1.5V) must match. Mismatched speeds force everything to the slower stick, and different voltages can cause instability.

Rank matters for dual-channel Mixing single and dual rank sticks usually works but may lose dual-channel mode. Match rank when possible.

Test used sticks before trusting them Used ECC sticks are a great deal, but run a memtest for a few hours first. A single bad bit can corrupt ZFS.

Don’t overthink it Grab a matching pair if you can, but brand alone won’t cause problems.