A controller for a Super Enhanced Endurance Device (SEED) or Solid-State Drive (SSD) increases flash endurance using a DRAM buffer. Host accesses to flash are intercepted by the controller and categorized as data types of paging files, temporary files, meta-data, and user data files, using address ranges and file extensions read from meta-data tables. Paging files and temporary files are optionally written to flash. Full-page and partial-page data are grouped into multi-page meta-pages by data type in the DRAM before storage by lower-level flash devices such as eMMC, UFS, or iSSD. Caches in the DRAM buffer for storing each data type are managed and flushed to the flash devices by the controller. Write dates are stored for pages or blocks for management functions. A spare/swap area in DRAM reduces flash wear. Reference voltages are adjusted when error correction fails.