memtester 4.3.0 User-space memory subsystem tester
Memtester stress-tests the memory subsystem of your operating system and computer. 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.
Memtester runs entirely in user space. This means that you don't need to reboot to test your memory, but also that it's not possible to test all of the RAM installed in the system.
It can also be told to test memory starting at a particular physical address.