Best recording studio software?

Hey yeah, I'm having similar problems with my older macbook pro. I love logic, and use it professionally but it really does work best (especially the latest version) on new macs. Anyhow, I would recommend you try Reaper. It is free to try and very inexpensive why you do buy it. It's way less memory and processor intensive than Logic, but doesn't come with a bunch of software instruments and plug-ins like Logic does. But it does support most plug-in formats out there and many are free! Also, despite it not having built in software instruments if all you are doing is recording and sequencing then Reaper provides more than enough capability.