Samsung Electronics announced today that it collaborated with Sun Microsystems to develop a SLC NAND flash memory with five times the endurance of conventional NAND flash memory. This would put the "ultra-endurance server-grade" flash memory at 500k program/erase cycles.
To extend the endurance, Samsung likely tweaked the underlying cell process and/or modified the programming algorithm. The net result is that the improved endurance comes at the expense of reduced performance or retention. However, by targeting high transactional enterprise applications with this device, the degraded retention should not be an issue.