Stands for "Error Correction Code." ECC is used to verify data transmissions by locating and correcting transmission errors. It is commonly used by RAM chips that include forward error correction (FEC), which ensures all the data being sent to and from the RAM is transmitted correctly.
ECC RAM or memory is similar to parity RAM, which includes a parity bit that validates the data being sent. The parity bit is a redundant binary value of 1 or 0 that is sent along with the data. If the parity bit does not match the value of the data it represents, it indicates an error in the transmission and the data may need to be resent. ECC works in a similar way, but uses a more advanced error correction system that can correct data transmission errors on the fly.
Since ECC memory requires more processing, it can be slower than non-ECC RAM and basic parity RAM. However, ECC RAM provides more reliable data transfers, which results is greater system stability. Therefore, high-end servers and workstations may use ECC memory to minimize crashes and system downtime.