is it memtest... or is there something better?

i just received 2 gb of RAM in the mail today, and it seems to working fine, in my "about this mac" window, it clearly says i have 2GB, which is good. but i'd still like to do a test.

so will memtest do the trick ?

edit: i just typed in memtest in ...and Rember 0.3.3 is shown instead?