1. I pretty much told you all I knew about these and gave you links above. Try Google for more information.

2. memtest (not testmem) runs as long as you will let it. It's a program called memtest86, and has some options to run different tests that affect how long each pass takes (as does, obviously, the processor used and the amount and type of memory). I'm not clear at all why you say you don't believe it. Again, memtest86 should get you a lot of information if used as a Google search term.