Cpu Load vs. System Load

[apetrocelli]

what's the difference between those two, in the Autmation window? What exactly do they measure?

[John H]

in my experience the CPU load measures the amount of CPU time the plug-ins are taking up, the system load covers the interface and background applications.

For instance, use a software synth like vibra 1000 with the hardware buffer set to 128 and the system load will show up as quite high once you add a lot of plug-ins etc... increase the buffer to 256 or above and the system load will go down and you'll also have a more responsive interface.

I'm only gauging this off how my beige G3 works in this way, a G4 with 100s on MBs of RAM is probably going to need to pushed a lot harder to show a high cpu and system load.

[apetrocelli]

ok, here's from the manual:

About Processing Bandwidth

Meters in the Automation Enable window indicate how much of your system’s processing power is being used in processing audio, and when writing and playing back automation. On Pro Tools LE-based systems,these meters show System Load and CPU processing capacity; on Pro ToolsTDM systems, they show System Load and PCI bus traffic.

As these meters approach their limits, recording or playback of automation data may be affected. If CPU Load or PCI Load are high, a System error may occur. If SystemLoad is high, Pro Tools may miss playbackof some of your automation data during particularly dense periods of activity.In both cases, to reduce processing load,you can first try deselecting the MovingFaders During Playback option in the Automation Preferences.
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That's a start. Still I don't understand what they actually are, and what the hidden window measures (command click on Sytem Load gauge).