I've got the same MacBook, and I wouldn't mind investing a few bucks to see if I get the same performance boost with my OS X 10.6.8.
Although
Crucial sticks to Apple's specs, they sell, but rate as incompatible,
this Dimm (which looks compatible despite their protestations), and
this OWC DIMM also looks to be the correct one, but I think I'd prefer a less expensive alternative to either; is
this the DIMM you bought from Fry's (which you spelled differently, so I'm not even certain I'm in the right place)?
Alternatively, can you suggest another less expensive (but reliable
) vendor if there is such a thing? (I've always used and been happy with Crucial, but since this is an experiment, and I don't run any particularly RAM intensive apps... )
Also, have you tried swapping your new RAM between slots to see whether there's any performance difference?
Thanks.