A method to check for redundancy in two or more data lines comprises receiving data on a first data line, computing a first cyclic redundancy check (CRC) value on the data of the first data line, performing an exclusive OR (XOR) function on the first CRC value with a stored memory value, and updating the stored memory value with a result of the XOR function, and repeating on additional data lines until a last line is processed such that an error is indicated if a final stored memory value is not zero. An apparatus to check that two cores are operating in lockstep comprises a first core comprising a first data checker, a second core comprising a second data checker, and a lockstep checker to compare an output of the first data checker with an output of the second data checker.