Memtest86+!

MemTest86 is a memory test for x86 computers.

GoldMemory is a self-bootable, DOS-based, standalone memory subsystem testing software.

DocMemory Diagnostic, an advanced self-bootable PC Memory Diagnostic Software is a rigorous test pattern exercises both the PC Base and Extended Memory to locate defective memory, all carried out without the need for user to disassemble memory from the PC.

M2K MemScope is a free memory testing software program from the makers of Micro-Scope - a large suite of professional, time tested (and expensive) computer diagnostic tools.

R.S.T. Pro2 is the definitive memory diagnostic and validation tool designed for the rigorous testing needs of desktop & server memory manufacturers, system builders, design engineers, and service professionals. Powerful new features and advanced functionality make R.S.T. Pro2 the most comprehensive memory validation tool of its kind. R.S.T. Pro2 is the tool of choice for numerous industry professionals who want to quickly and accurately test and validate memory in all Desktop, Workstation and Server PC’s incorporating an Intel or AMD x86 compatible 32/64-bit single/multi-core processor. »

The Windows Memory Diagnostic tests the Random Access Memory (RAM) on your computer for errors. The diagnostic includes a comprehensive set of memory tests. If you are experiencing problems while running Windows, you can use the diagnostic to determine whether the problems are caused by failing hardware, such as RAM or the memory system of your motherboard. Windows Memory Diagnostic is designed to be easy and fast. On most configurations, you can download the diagnostic, read the documentation, run the test and complete the first test pass in less than 30 minutes. »