My computer is CHOKING up every time I listen in Logic

Please tell me what I am doing wrong. I have a fully RAMmed out late 2013 iMac running Logic X. I am working on a fast piece with Albion 1 and Action Strikes. I have my sound libraries on an external drive with USB 3. I'm working on a piece and the computer chokes and chokes. I can barely play 4 measures without the computer hiccuping. I have NO other programs running.

Is an iMac simply to slow to run a dozen tracks?

Thanks for the help.

 

Lots of things to check. What's your buffer size? (Try a higher buffer size.) Is it one specific instrument that's glitching? Check Kontakt's streaming and CPU meters at the top of the interface. Is one of them peaking? This gives you a clue into what the cause of the glitching is.

 

Thank you very much. I will try that ASAP.