ECC RAM is not a free pass on memtest86.

No, ECC doesn’t mean you can skip memtest86.

ECC corrects single-bit errors and detects double-bit ones, but that’s active protection—not a certification that your RAM sticks are flawless. Memtest86 uncovers physical defects, timing issues, or intermittent faults that ECC might quietly correct or not even log. A marginal stick that works fine under correction today can get worse over time.

I’d still run memtest86 on new ECC RAM before trusting it in production, and again if you see kernel panics or unexplained reboots. ECC is a safety net, not a blanket pass.

Your data is worth the hour or two it takes.