diglloydTools is a suite of three software utilities for for OS X.
require 10.6 through OS X 10.11 El Capitan. The latest version is tested/qualified for OS X 10.9 and 10.10 and 10.11, but older versions can be downloaded for use back to OSX 10.6.
At their most powerful using the command line (Terminal), GUI wrappers are also provided also.
DiskTester is performance testing software for your hard drives and solid state drives, especially RAID. DiskTester will tell you how your drives are performing, map out bad sectors, and help track down problems. DiskTester can also recondition an SSD quickly and conveniently.
MemoryTester enables you to stress-test your memory and Mac before you put it into "production" use. It helps prove that the machine and memory are reliable. No other tool can push the machine to its limits like MemoryTester can.
IntegrityChecker enables you to verify your files and backups, detecting even single-bit errors. With IntegrityChecker, you can be sure that the files you have copied, backed-up or restored are perfect, even years later.