The Samsung 850 EVO was a solid-state drive in the 2.5" form factor, launched on December 8th, 2014, that is no longer in production. It was available in capacities ranging from 120 GB to 2 TB. This page reports specifications for the 250 GB variant. With the rest of the system, the Samsung 850 EVO interfaces using a SATA 6 Gbps connection. The SSD controller is the MGX (S4LN062X01) from Samsung, a DRAM cache chip is available. Samsung has installed 32-layer TLC NAND flash on the 850 EVO, the flash chips are made by Samsung. Please note that this SSD is sold in multiple variants with different NAND flash or controller, which could affect performance, the "Notes" section at the end of this page has more info. To improve write speeds, a pseudo-SLC cache is used, so bursts of incoming writes are soaked up more quickly. The cache is sized at 3 GB, once it is full, writes complete at 300 MB/s. The 850 EVO is rated for sequential read speeds of up to 540 MB/s and 520 MB/s write; random IOPS reach up to 97K for reads and 88K for writes.
At its launch, the SSD was priced at 150 USD. The warranty length is set to five years, which is an excellent warranty period. Samsung guarantees an endurance rating of 75 TBW, a relatively low value compared to other SSDs.