Memtest86
Memtest86 is a free software, with which you can check the contents of your computer for errors.
It was written by Chris Brady and is licensed under the GNU General Public License.
The program can check memory by means of a stress test for errors and optionally display the memory address of faulty or defective memory cells in a list. The software is started and executed immediately after the system startup; an operating system is not required.
Furthermore Memtest86 is included in the boot menu of some Linux distributions by default.
Operation
Memtest86 writes a series of test patterns in each memory address, reads again and compares them. Only when the read pattern matches the original writing, the memory address in question is error-free. This process is repeated for each memory address; are all error-free, so even the memory module with the greatest probability is error-free. A Memtest pass ( "Pass" ) can take several hours depending on the CPU speed and memory size. A total of nine different tests are performed.
Because of the way of Memtest defects found do not necessarily mean a defective memory. It may be a defect in the CPU or the motherboard Also, the RAM is the most common by far of failure.
Memtest86 can be started from a CD, but there are also versions that are designed for USB flash drive and floppy disk available.
Memtest86
Memtest86 is a spin-off, written by Samuel Demeulemeester, based on the version 3.0 of Chris Brady Memtest86. The project was developed because the original of May 2002 had not been updated to March 2004. Memtest86 is like his master under the GNU General Public License. Since version 4.10 Memtest86 is offered with installer for memory cards and USB flash drives. After a long break the original Memtest86 is now again developed. Both programs are compatible with all current chipsets for all Intel and AMD multi-core processors.
Memtest for graphics cards / GPUs
With CUDA GPU memtest has been around for some time, a memory test program for the memory to graphics cards.