2007 macbook pro 3 second freeze

i recently purchased a 2007 macbook pro used (obviously). it's running mountain lion, with 3g of ram, 2.2ghz core two duo.

the problem...

i do electronic music with various programs and instruments and controllers.. but none of that seems to be the root of this problem.. that's pretty much all i'm using this computer for though, is music applications.. traktor 2, ableton 8 suite, and maschine.. every half hour or so, everything locks up for about 3-5 seconds, and then picks back up where it left off.. i've mostly noticed it in traktor, but that is just what i've been using the most.. it has also done it while in ableton, while using maschine in stand alone, and also while playing a mp4 file using quicktime..

please help??

thanks!!

dave