MemTest86 and Memtest86+ are memory test software programs designed to test and stress test an x86 architecture computer's random-access memory (RAM) for errors, by writing test patterns to most memory addresses, reading back the data, and comparing for errors.[1] Each tries to verify that the RAM will accept and correctly retain arbitrary patterns of data written to it, that there are no errors where different bits of memory interact, and that there are no conflicts between memory addresses.

A screenshot of MemTest86
Developer(s)PassMark Software
Stable release
9.1 (Build 1000) / May 21, 2021; 4 months ago (2021-05-21)
Written inC and assembly
LicenseProprietary software
A screenshot of Memtest86+
Developer(s)Samuel Demeulemeester
Stable release
5.01 / September 27, 2013; 7 years ago (2013-09-27)
Preview release
5.31b / April 12, 2020; 17 months ago (2020-04-12)
Written inC and assembly
LicenseGPL v2.0