The Micron P420m, announced earlier this summer, is a half-height, half-length (HHHL) PCIe storage device that augments Micron's PCIe enterprise storage line. The P420m has a lot to live up to. If you remember back to last October, we reviewed the Micron P320h and came away thoroughly impressed. Massive amounts of speed, endurance and parallelism were at our disposal. With the P420m, Micron is at it again, but this time they brought MLC NAND to the table instead of the bulletproof SLC NAND they used in the P320h.