Macbook Upgraded to Yosemite, now Logic 9 stalls

Question

I have an older macbook pro (2009) that was running fine on Mountain Lion with Logic 9. I upgraded to Yosemite, and now Logic 9 stalls when playing songs, gives me "processor overload" errors when playing songs that used to run fine on Mountain Lion, and keeps playing songs even when the stop button is pressed, only after about ten or fifteen seconds will it do the command I enter (stop, pause, etc.)..... My question is, until i can afford a new mac, will I save on processor power by purchasing a stereo digital audio converter instead of using the internal one? Im thinking my mac isn't fast enough or powerful enough to run yosemite AND logic, as is evident by the amount of errors I am experiencing. (BTW, this was done with a fresh install on a clean drive I had security erased, so there shouldn't be any extension conflicts, I loaded up logic first to see if i would keep getting the processor errors and I do.) SO, my choices are to reinstall Mountain Lion, or to buy a digital stereo audio converter. Will the converter transfer all of the processing from the internal CPU to the converter , and if so, will it be enough so that Logic will run smoothly?
Thanks for any help,
Ivan

Answer 1

Well, I got rid of Yosemite, erased my drive, and loaded up mountain lion PLUS installed a SSD per the Apple referred dealer, and the Mac clocks like a champ. HOWEVER, Logic is STILL stalling on the "stop" button, whether I use the space bar or the transport, and no other buttons or commands fail. It seems to stop whenever I load it up with a new process (add a reverb, delay, softsynth, etc.), but if I am normally playing back a track, it works fine. It seems to get worse as the session goes on (first ten seconds, then twenty, then thirty, the last time I had to leave it completely and it went on for five minutes.).  When it's ready, it runs through the commands I've pressed one at a time in rapid succession. First it will scroll to the next plug in preset (per the "next " button I pressed when it first jammed), then it will stop (because I pressed the "stop" button) then it will start again (because I tried pressing the spacebar after that) then it will do as many of the commands as I pressed, about two per second, until the last command I entered is completed, and if I press the spacebar an even number of times, it will simply start playing again. Ever heard of something like this?
p.s. would you recommend a new MOTU (I've always liked them) or have you heard good things about the Native Instruments digital stereo I/O? Or the Apogee? I think I'm going to just buy a whole new system, I'm getting more soundtrack work and as fun as trying to fix problems are and as much as I'm learning, It;s probabaly time to throw away the duct tape and bubble gum and step up. Mac even offers special pricing for college students. I get a whole twenty bucks off a new mac. Oh, thank you, mighty apple.
Thanks for your help. You guys get points or something for answering questions, right? Does that turn into anything tangible, like software or discounts, or is it like a status thing (I'm an online poker player, and we get pretty vicious during tournaments even though there's no money, everyone wants first place).
Ivan