It´s wise to check your system components when you first start your new computer. It does not matter if you build it yourself or purchased a prebuild computer. It´s always a good idea to check if everything is working as intended. MemTest 3.4 tests your systems memory to make sure it is not damaged. It´s also a great way to test it when you overclock your computer / ram. This way you can ensure that it´s still reliable and does not produce errors.
