ECC stands for Error Correction Code, and in the context of computer memory it indicates the ability to detect and correct minor errors. This dramatically increases the reliability of the memory system, which is highly desirable in environments where computers are performing critical functions. There is a small amount of overhead when using ECC memory, so performance takes a slight hit compared to non-ECC options, but the trade-off is well worth it for servers and some workstations.

Further, Registered memory - sometimes also called Buffered memory - puts less of an electrical load on the memory controller chip in a computer. This in turn allows the use of much larger amounts of memory, and so is needed when utilizing all of the memory slots on higher-end server and workstation motherboards.