The drive offers double the capacity of the previous 850 EVO and will reach sequential read and write speeds of 540MBps and 520MBps, respectively—pretty much the max of the SATA interface.
SATA, of course, is the key word here. Samsung has been shipping a near 16TB drive (which you can read about here) for months already, but that drive runs on the server- and workstation-focused SAS interface. The 850 EVO's SATA interface and 2.5-inch form factor make it an ideal solution for consumer desktops.
Samsung has also had a 3.84TB SATA SSD available since last year, but it's built for datacenter use, supports far more writes than consumer drives, and costs more. With the new 4TB 850 EVO, Samsung uses its well-respected V-NAND and rates it for 300 terabytes written.
In performance, the 850 EVO can’t touch drives running on the M.2, U.2, or PCIe interfaces, but for capacity it can’t be beat today.
Naturally, you want to know the price. Samsung said the list price of the 4TB 850 EVO will be $1,500 with a five-year warranty. For comparison, the current 2TB 850 EVO sells for $675 on Amazon, so that price seems in-line.
Why this matters: Everyone is waiting for the day when they no longer need hard drives for bulk storage, and with SSD capacities creeping ever higher, this is another possible nail in the coffin of magnetic media.