RAM Swap Between Core 2 Duo and i5 13" MacBook Pros

Question

Hi!
We have two MacBook Pro's at work. One is a late-2010 13" MacBook Pro with an 2.4GHz Intel Core 2 Duo processor. The other is an early-2011 13" MacBook Pro with an 2.3GHz Intel i5 processor.
What we'd like to do is upgrade the i5 to 8GB of RAM and more the 4GB from the i5 to the Core 2 Duo, which currently has only 2GB.
The memory modules for both are the same pin set, but seem to be different speeds - one is 1066Hz, the other is 1333Hz. What I'm looking to find out, before I purchase anything, is if the memory that came installed in the i5 MacBook Pro will work in the Core 2 Duo MacBook Pro.
Any help you can give would be great!
Thanks!
-Eric

Answer 1

Hi Eric,
I have not tried those specific machines, but in the past I have done what you're asking about. In those days there used to be called "dual programmed" RAM. I've had several Macs that the RAM was interchangeable on; if installed in the lower speed machine, it would run at the lower speed; if installed on the higher speed machine it would run at the higher speed. BUT, it was also possible to buy different brands of RAM that were not interchangeable in those same Macs; one model/brand of RAM worked in one of the Macs, one worked in the other, but neither worked in the the opposite machine.
Where does that leave you? I believe it's possible the faster RAM will work in the slower machine. Unless it's "dual programmed" as I described, I doubt the slower RAM will function properly in the faster machine (and if it did, it might function at the slower bus speed = not good), but that doesn't appear to matter to what you want to do.
I do not know for sure that it is "safe" to try the faster RAM in the slower machine, but based on other posts I've read, I wouldn't be afraid to try it. Note that if it does funtion properly, it isn't going to be at the faster speed (1333MHz); that's something you can check in System Profiler if you decide to try it. If you do, I'd watch it carefully for awhile to make sure data/HD and basic functions are not being affected by it; I would perform a backup just prior to installing it, then not backup over it. That way, if anything goes amiss, you can just swap the RAM back to original (or purchase more) and restore from the "good" backup.
Just some thoughts.
What would be better is to hear from someone who's actually done it with that RAM/those machines. Good luck to you.