Well, the friend would say that the best solution to System Overload issue is to switch to Pro Tools/Cubase, but to those who are not loosing faith in Logic the following is dedicated.
The answer is veeeery simple. I’ve been fighting with it for a month and have finally found the motherfucker who’d been doing it. Superior Drummer. Yeah, it’s just a plugin in Logic, I use it for drums. Now, follow the story how to find the motherfucker in your case, it’s universal.
1. Open session you have System Overload message with. Press Alt+X, this will show you the CPU and disk monitor. Push Play and you will definitely see one of the stripes goes beyond the ceiling, and then the System Overload message following.
2. Switch off plugins in your session one by one, restarting playback when interrupted by System Overload. Start with ones you have in Output channel (the last one, if you have ones) and Instruments (drums, basses, synths, whatever) and then go to the rest, until you have the peak on the CPU monitor down. Remember what was the last plugin you switched off. This is the motherfucker.
3. Quit Logic without saving the project and reinstall the motherfucker. Try to find new installer. In my case I had Superior Drummer 2.0 and then several partial updates to 2.3. To solve the problem I’ve downloaded installer which contains 2.3 full version. Restart Logic and see if the problem persists.
UPD: Well, Logic is a piece of crap if to speak about multithreading. When I started processing Superior Drummer tracks (btw, it can’t be frozen as the rest of plugins) I faced the dilemma that my voracios Drummer plugin was processed with the only one virtual core as well as very greedy CLA drums of Waves and nothing could be done to split them between the cores. So, I’ve got the situation when one core is working till the whole system is overloaded whilst the rest of them are chilling and smoking bamboo. For me the only solution was to use built-in Drummer’s Bounce feature to transfer audio files to the project and mute and disable initial MIDI track in case I wish to change something in my drum part.
All mentioned above refers to both versions of Logic, 9 and X. I haven’t tested these particular plugins in Pro Tools or Cubase, but I definitely will. I can’t believe that all DAWs will behave like that, that’s a fiasco.
UPD2: I’m a looser. I’ve set project frequency settings to 96 000, while my card does not support it _natively_. It took a couple of weeks to find out that my Line6 card has been working with permanent realtime converter, which “ate” the most of CPU. Fuck me.