Memtest 4.23

Memtest 4.23 supports MacOS X versions 10.7 Lion through 10.12.x Sierra on Intel-based Macs. The download package contains universal binary support for both 32-bit and 64-bit versions of MacOS X. Note: Users running MacOS X 10.6.8 or earlier and/or PowerPC-based Macs must download Memtest 4.22.


Memtest OSX is the best ram-testing utility for the Macintosh platform with the ability to find intermittent memory problems that are the frequent cause of unexplained crashes or freezes in Macs. Memtest can identify random memory problems that commercially available utilities miss including defective motherboard CPU cache memory. Memtest is distributed as a universal (fat) binary containing two separate executables supporting 32-bit and 64-bit Intel-based Macs. The appropriate machine-specific executable is loaded by OS X at launch time. Upgraded and new features in version 4.23 include:

- Significant reduction in the execution time of the "quick" option. Use of this option results in completion of the test sequence in 1/3 the normal run time with minimal impact on the reliability of the test results. As always, use of the full test sequence is highly recommended for detection of random, intermittent failures. The "quick" option provides a fast alternative to run test sequences more frequently when minimal downtime is desired.

- Addition of the "-h" help switch which lists a summary of the memtest command line switch options and usage examples.

Memtest executes in 64-bit mode on all Macs running 64-bit MacOS X allowing virtually all of the installed ram to be tested. On systems running 32-bit MacOS X, memtest is restricted to a maximum testable limit of 2 GB.

User feedback and developer contributions are always welcome and greatly appreciated.