The disclosure is directed to a system and method for storing and processing check-node unit (CNU) messages utilizing random access memory (RAM). A decoder includes a layered array of CNUs configured to receive at least one variable-node unit (VNU) message associated with decoded bits of at least one data segment being operated upon by the decoder. The decoder further includes a CNU message converter configured to permutate at least one initial circulant of the VNU message to generate a converted CNU message having sub-circulants sized for RAM-based processing. The decoder further includes RAM configured to store sub-circulants of the converted CNU message at addressable memory blocks for parallel VNU processing.