A processor or other apparatus of an aspect may include a first cache, a first error correction code (ECC) logic for the first cache, a second cache, and a second ECC logic for the second cache. The apparatus may also include an interconnect coupled with or between the first cache and the second cache. The interconnect is operable to transmit data and also check bits corresponding to the data between the first cache and the second cache. A method of an aspect may include accessing data, and check bits corresponding to the data, from a first cache. The data and the check bits may be transmitted over an interconnect from the first cache to a second cache. The data and the check bits may be stored in the second cache. Other methods, apparatus, and systems are also disclosed.