HP have released a new NVMe M.2 SSD, the EX920 which uses Silcon Motion's SM2622 controller and a DDR3-1600 cache which scales directly with the size of the drive, the 256GB drive has a 256MB cache while the 2TB has 2GB.  The drive uses four PCIe Gen 3 lanes, which offers some very impressive performance, Benchmark Reviews measured 3183/1776 MBps read/write in CrystalDiskMark.   The only real drawback to this drive is the warranty; while most companies offer at least five years, this HP drive is only covered for three.

"HP suggests sustained sequential read speeds up to 3200 MB/s, and sustained sequential writes up to 1800 MB/s from their 1TB EX920 SSD, which utilizes 64-layer 3D NAND to deliver impressive storage density and reliability. Relative to solid state storage, one terabyte is an enormous amount of near-instant drive capacity. We’ll see if HP’s EX920 M.2 SSD is worth the money."

Here are some more Storage reviews from around the web:

Storage