US Patent 9720754 Read level grouping for increased flash performance

A table of error counts is generated based on reading wordlines of a flash memory device, the table storing an error count for each combination of wordline and respective read level voltage used to read the wordlines. A plurality of offset wordline groups are generated based on the table of error counts, with each group associating a different read level offset voltage with a plurality of wordline addresses. A storage device is configured to read memory cells using a read level offset voltage of a generated offset wordline group associated with a wordline address of the memory cells to be read. After a predetermined point in a life cycle of a respective memory block, the table is regenerated and plurality of offset wordline groups are regenerated based the regenerated table of error counts.