Non-volatile memory and method having block management with hot/cold data sorting

A non-volatile memory for storing units of data, comprising:

• a memory array organized into blocks of memory cells that are erasable together;
• said memory array being partitioned the non-volatile memory into a SLC portion and an MLC portion, where memory cells in the SLC portion each stores one bit of data and memory cells in the MLC portion each stores more than one bit of data and for storing data logical group by logical group in each block of the SLC portion;
• first and second operational layers in the SLC portion and a third operational layer in the MLC portion;
• a plurality of logical groups provided by partitioning a logical address space of the host into non-overlapping groups of sequential logical addresses, wherein multiple logical groups are storable in each block and each logical group having a plurality of corresponding logical pages;
• the first operational layer for initially storing host data being written and for subsequently relocating therefrom the host data logical-group by logical-group into the second or third layers;
• and
• a state machine controlling operations that include:
• ranking each logical group by assigning a temperature, the temperature being determined as a function of a time stamp value and potential for future rewrites of each logical group, the time stamp providing a relative measure of how recently written in is each of the logical group, and where a higher temperature indicates a higher probability that the logical group will suffer subsequent rewrites due to garbage collection operations;
• and
• evicting a logical group from the second operational layer to the third operational layer in a manner dependent on the temperature associated with the logical group being evicted.