Memtest86+ provides a more thorough memory check than
 that provided by BIOS memory tests. Can be loaded and run either
 directly by a PC BIOS (legacy or UEFI) or via an intermediate
 bootloader.
 .
 This tester runs independently of any OS - it is run at computer
 boot-up, so that it can test *all* of your memory. You may want to
 look at `memtester', which allows one to test your memory within Linux,
 but this one won't be able to test your whole RAM.
 .
 It can output a list of bad RAM regions usable by the BadRAM kernel
 patch, so that you can still use your old RAM with one or two bad bits.