I ordered a hard disk and tested through the Crystal Disk benchmark. It was only giving 50% less speeds than specifications. I have a 5 yr old Samsung SSD with same operating system which was reading above 500MB/S for the sequential test. I have run the same test with another Samsung SSD 850 EVO, which also gave above 500MB/s. I made sure that all the parameters are same for different SSDs. I got a replacement disk from amazon and it turned to be defective as well. I tried one from Best Buy released in the same month and discovered the same. Samsung's Quality testing has gone downhill and they should be ashamed of themselves for selling so many defective units. Before a person from Samsung replies to my comment, they should also note that I have already contacted Samsung and they said the issue can't be fixed and to return the drive.
I appreciate you contacting Samsung with your concern. Your feedback will be reviewed with our product team.
Samsung products are engineered to the highest standards of performance and quality and we back this SSD model with a 5-year limited manufacturer's warranty, if purchased brand-new from an authorized dealer.