Logic Pro X cpu woes

Back in the days of Logic 9 and my 2010 MBP, all was well. I never had single processor spikes (or, rather 'balloons'--since they come on slowly) such as I get every time I run Logic Pro X. I'm hoping that someone will have just the bit of advice I need--the posts I've read thus far haven't done the trick.

I've now got the latest MBP (2.7 ghz 4 core i7) with 16 gigs of ram--8 possible threads. SSD. And I've got LPX now. OS: 10.8.5. So, on paper at least, things should be much better, with a much faster MBP and more memory and the new version of Logic. No luck. With a single instance of Kontakt and a single reverb (on an Aux channel, to try to have the load passed to another processor) I'll play for a couple of minutes and then, tidal wave style, the processor will climb climb climb until I hear clicks and pops, and then settle back down as if nothing had happened. There's no huge background process running, no strange audio routing plugins. Just core audio, Logic, and me. I'm a bit depressed about all this, since I can't do the most basic things (let alone run a big complex mix).

I'd be grateful for any troubleshooting steps (I've seen the apple issued docs about distributing load to multiple threads; no help, alas).

Many thanks.