Which of the following memory technologies has the HIGHEST cost to implement?

ECC memory adds a small number of extra chips for parity and error correction, resulting in only a modest cost premium over standard RAM and far less expenditure than a full memory mirror.

Memory RAID mirroring requires an identical capacity of DIMMs to mirror all data in real time, doubling the total memory investment for any given usable capacity. Unlike ECC, which adds only minimal overhead chips for error correction, memory RAID demands a fully redundant set of modules, making it the most expensive memory protection technology to implement.

Memory pairing (interleaving) involves installing matched DIMMs in pairs to improve throughput and does not require duplicating the entire memory population, keeping costs well below RAID mirroring.

Registered (buffered) memory adds a register component to each DIMM to support larger memory populations, which raises per-DIMM cost slightly but does not require doubling total installed capacity the way RAID mirroring does.