memtest86+ 5.01 Thorough real-mode memory tester
Memtest86+ is a thorough, stand-alone memory test for x86 systems. It repeatedly writes different patterns to all memory locations, reads them back again, and verifies whether the result is the same as what was written. This can help debug even intermittent and non-deterministic errors.
It runs independently of any operating system, at computer boot-up, so that it can scan as much of your RAM as possible for hardware defects.
Memtest86+ cannot currently be used on computers booted with UEFI.