ECC RAM vs non-ECC RAM: Mixing is a bad gamble

Mixing ECC and non-ECC RAM usually disables ECC entirely, treating both as plain DDR. The memory controller wasn’t validated for that mix, so you risk random crashes, boot loops, or a system that only works with one stick. If ECC matters, use all ECC sticks; if not, buy regular RAM—mixing saves no money and adds an unnecessary variable. A clean configuration is the safer bet.