9 Replies Latest reply: Aug 6, 2008 2:31 PM by xearthlingx
Duane Morrison Level 1 (10 points)
I posted a question about this in another thread but haven't heard anything back yet - and am desperate for answers so figured I'd try again!

I've just started having a big problem with CPU spikes, seemingly out of the blue.

After having had no problems (that have affected my workflow at least) since updating to Logic 8 when it first came out, the last 2 songs I've worked on have both started having repeated CPU spikes. In both cases the songs (which have for the previous couple of weeks been running fine as I've worked on them) suddenly seem to reach some kind of critical mass and stop at least 4 or 5 times in the song (with a processor overload) making it impossible to mix. The spikes themselves appear to occur every 10 seconds or so.

Though the songs have previously been fine during sections with many tracks, plugins and instruments running, once this starts happening even the most sparse sections can suddenly no longer play without overloading.

In the past, bouncing any instruments to audio or freezing processor-intensive tracks would clearly lessen the load and allow the song to play without a hiccup, but it seems once this starts happening that any attempts I make to pare the song back barely help at all. Even if, in between spikes, the song is running with about 25% max on the CPU meter, when a spike comes both processors momentarily max out and stop the track.

Strangely, with the latest song, even reverting to previous versions (ie from a few days ago when I was having absolutely no problems of this kind) the computer can suddenly no longer cope with the spikes (which I assume have been happening all along but haven't affected playback before now). Weird but true.

I've tried disabling all audio unit plug ins in AU manager, setting all channel strip inputs to no input, running the song using Core Audio rather than the MOTU 828 and repairing permissions with DiskUtility.

Today I tried a clean install of 10.5.3 and 8.0.2 on a new drive (no 3rd party plugins or ANYTHING apart from Logic and OSX installed) - still with exactly the same result.

I've even tried copying all the audio from the arrange into a brand new song, adding the plugins and routing to busses track by track, all the while keeping an eye on the CPU meter. As soon as I've sent just a couple of tracks to aux channels and added only 3 or 4 instances of Channel EQ and Compressor I notice the spiking begin. It's clear that by the time I've finished the setting up of the song the spikes will be maxing out again.

I realise I'm running an old machine (ie Dual 1G G4) but it has, up until now, been working spot on under the current system (I've been using 10.4.11 and hadn't updated to Leopard until today cos I haven't wanted to upset the delicate equilibrium!)

Thankfully I've found a clunky workaround by copying the song on to my Macbook and running that in my studio - a lifesaver but not satisfactory. (I can see the spikes on the Macbook too but playback isn't affected).

I've been using Logic forever and know this behaviour (and unresponsiveness to all my troubleshooting attempts) isn't normal!

I've seen the threads from a few months back but am wondering is anybody else out there still having similar issues? Or has anyone had them and solved them?

Please help!


PowerPC G4 (2.1), Mac OS X (10.5.3), 2GB RAM
  • xearthlingx Level 1 (135 points)
    The latest? It's still spikes constantly here. IMHO, I think there is an issue with-in LP 8 itself with symetric multi-tasking to more than one core... evenly distributing the load between cores. It's hit or miss with me & completely un-predictable and random (the CPU spikes). I've tried all the same quick fixes or work-arounds, of which none seem to make any difference at all. Even setting core audio buffer to 1024 & disabling safety buffer.

    Oddly I do find it interesting that on my system anyway, Ivory 1.7 & Atmosphere 1.2, once initially instantiated on an inst track, will consistently evenly distribute between both cores (I have a dual core machine)... and never spike the CPU, no matter how much polyphony I use on either one, with the core audio buffer set to 128. There has to be something the way these two virtual synth plugs are coded differently, to utilize an even symetric threading or distribution to multi cores. -> I am no computer wiz tech head by any means, but this is the best way I can explain it.

    Fresh clean install of OSX Leopard 10.5.4 / 2.5GB Ram / LP 8.0.2 / Digi Core Audio 7.4 / Digi 002R
  • fermusic ( points)
    No Cpu spikes at all!
    Everithing perfect here!

  • fermusic ( points)
    oops.. but you are on G4???

    I don't know anything about that..
    I nerver check Leopard and Logic on G4 CPU!

    In any case there are no problems with 3rd party plugins...
    there is some digidesign -NI Kontakt and Waves and some other problem...

    but this is "only" Logic forum...

    ask to their respective software house factory support for more info about the related issue

  • Noah Perry Level 1 (70 points)
    That same thing has happened to me too. I'm on a Dual PreIntel g5 with 5gb of RAM. Logic 8 and 10.4.11.

    The song plays fine a million times then one day it hates it. Or I add one little automation dot or the subtle tweak of an already existing plugin and the machine can't handle the song anymore. I freeze a BUNCH of tracks and it's like it's not even recognized by the CPU meter. Still spiking randomly from 10% to 110% in a millisecond. Not always but sometimes. I even get it random spikes when recording a stereo acoustic guitar with a drum click playing on UltraBeat. Bummer. Still waiting for the stability to be "PRO". Lots of other stuff in Logic is PRO for sure, but it ain't the stability.

  • ambient8 Level 2 (295 points)
    One thing to look out for is too much DSP on a track. A thread cannot be split across multiple processors. If one of your tracks has too much DSP on it it will cause a core audio overload when it runs out of CPU. Also if you have any other tracks armed or input monitoring enabled, disable them. Logic reserves a CPU for recording if track is armed or input monitoring is enabled which will take away from your DSP capability.

    In case you were unaware..... Bussing reverbs and delays will help a lot and also freezing tracks that you are not working on at the moment will help reserve CPU for the "tasks at hand". Any AUs that are heavy load on the CPU can potentially overload a processor as well. There are a few that are still not playing with Logic well since the re-write for LP8. In that situation it could be either Apple changed or broke code that they need to address or the developer may need to update code to the current AU spec.

    Hope this helps.
  • steve shadforth1 Level 2 (175 points)
    its been said a zillion times.

    1. Turn airport off
    2. Disconnect from the internet (even if safari closed), I even used to physically disconnect
    3. Use less hungry reverbs if possible
    4. Close all other open programs.
    5. Turn off Latency Comp (if you can away with it), till you're finished tracking
    6. Turn Grid off if you do without it
    7. Turn off icons, do you really need them, a picture of a synth is pretty, but.........
    8. Buss FX when you can
    9. Set your buffer appropriately

    good luck


    Sign in, vote the mixes, and try some youurself!
  • Duane Morrison Level 1 (10 points)
    Cheers all for the advice..have tried pretty much all those fixes to no avail though.

    Noah, you've pretty much described the problem I'm having exactly. Song perfect for a million plays, then, in a moment, cursed with the spiking CPU to the point of unplayability. No amount of plugin removal, freezing etc makes any significant difference. And once it happens it seems there's no return to a non-spiking version.

    Have tried the affected songs under both Tiger and Leopard, with and without 3rd party plug ins installed, internet disconnected etc - and also on a friend's comparable system - and I'm almost certain that it is a corruption that occurs within the song or it's audio.

    I'm comforted to hear that others might be experiencing the same issue
  • fermusic ( points)
    I'm on Leopard 10.5,4

    I have no spikes!!!

    everithing works perfect! Your issue is related with some 3rd party plugs and 10.4.11

    I have no crash at all!!!
    Logic works fine!
    CPU is quite!
    Stabilty is EXCELLENT!!!

    I suggest to buy Leopard
  • xearthlingx Level 1 (135 points)
    Duane - Same exact problem I have. The CPU spiking is completely random... it seems like it has a mind of it's own or something. I could be working on a project in LP 8 (8.0.3) literally for 8-10 hours straight with no spikes, then the next day I open up the same exact project & it spikes the CPU from the get go. I had Tiger w/LP 8.0.3 & now Leopard 10.5.4... absolutely no difference. Same periodic spikes.