Getting Logic To Use The Second Processor, On OS9 9 Logic doesn´t use the second... Options

[pjsaccone]

On my dual 1ghz g4 running Logic, when one processor is fully loaded and it overloads, the system overloads instead of sharing the load with the second processor. Any tricks on making the plugins load on the second p???

Thanx

[lepetitmartien]

Logic under OS9 uses one processor for MIDI and the other for audio…
DP share works between both processors.
PT sees only one processor.
I don't remember for Cubase.

[rickenbacker]

There is a known trick to it and here it is:

turns out to be rather simple, and no Logic Control is necessary. every dual Mac owner can almost double his/her CPU performance by doing this (i say almost as the 2nd CPU does have other things to do other than process Logic effects. and, sadly, this only really helps with Bus DSP - not synths/samplers).

so, here are the steps:

1. open your Autoload

2. in the Environment, create a new Audio Object from the New menu

3. in the "Audio Object" box on the left side of the screen (the one that lists Audio Object, then Icon, then Dev...) click on the "Cha" menu (where it probably says "Track 1") and scroll down to "stereo inputs" and select any unused inputs on your system (on mine, that is input 7,8).

4. double click on the Audio Object icon in the Environment window - you should now see a full channel strip without the record button. this is good.

5. insert sends from this channel to any Buses that you want to run on CPU 2. (i send to Buses 1, 2, and 3 - you can always change this later). you can keep the bus sends set to a level of "-infinity" and even option-click each bus so it is disarmed.

6. save your autoload.

now, on any new songs you create, any/all effects you run on buses 1,2, and 3 (or whatever you sent to) will always be processed by the second processor. of course, you can manually add this "audio object" to any old songs and get the dual CPU advantage.

this works in 5.5 on both 9 and X. (i had trouble importing a bounce in X before, but it turns out that was a harddrive problem, not a logic problem. i saved to a different harddrive and it works like a charm)

no Logic Control is necessary. no 'record enabling' an audio channel is necessary. set this up and it just works.


And here's some more info that might help:

1. make sure you have the multiprocessor enabled in the audio hardware menu.

2. pick a track which you'd like to run on the second processor - doesn't matter if it is audio or an audio instrument (Logic or VST or AU). doesn't matter if it has other plugs on the track - they'll be sent to the second CPU too.

3. insert the I/O plug in (you can find here: Logic-Helper-I/O) just as you would any other plug in like a PlatinumVerb or a Multipressor.

4. in the I/O plug in window, select a channel for audio output (doesn't matter which - i select 1,2).

5. then bypass the I/O plug in - either by selecting Bypass at the top of the I/O plug in window, or by option clicking on its name in the channelstrip of the track in the mixer.

now, Logic will always process that track on the second CPU.

keep in mind that Logic will also process any Bus effects that the above channel is sending to on the 2nd CPU now too.

so it is possible now to overload the processing of the 2nd CPU - remember logic always assigns the processing for a 'selected' AI track AND it's assigned bus DSP to the second CPU. so if you've already assigned a lot of processing to the 2nd CPU (say a couple of FM-7s with effects which send to an Altiverb), and you select a different AI (say an ES2 sending to a Waves delay) - the computer will add the ES2 and Waves delay to the 2nd CPU and this 'spike' can bring things to a halt. admittedly, with a little attention, this shouldn't happen often - but it is worth keeping in the back of your mind. it is also MUCH easier to watch this distribution in Logic/ OS9 than Logic/X. since the dual CPU meters in the system performance window were combined into one CPU meter in Logic 5.4 + 5.5 on X, it is much tougher to actually see how much processing is assigned to each processor. but with a little time and patience, you should get a feel for your computer.

still, combined with this trick logic now has the depth in multiprocessing that it has in all other areas. the end user can now select just how much of the 2nd CPU he/she wants to use - if any - and how he/she wants to use it.

so figure out what works best for you and work away. combined with the coming, simplified 'freeze' function - this should really secure your dual 450 for some time.

I got all this from a Logic forum, so respect to the original posters.