Question about cpu usage and plugins

[Shanegrla]

This is kind of a noob question but it would be very helpful for me to help allocate my resources in my sessions when they're getting full, to know which tracks/plugins to disable first etc., if necessary:

Do plugins suck cpu juice from the second they're plugged in, or only specifically where there is audio passing through them on the track?

i.e., say I have a digirack compressor inserted into a drum track (where audio is being played consistently throughout the whole song), and then I have another of the same compressor inserted into a lead guitar track where there is only audio during the guitar solo (once in the whole song). Hypothetically, given the compressor settings are the same, are the two plugins using the same amount of juice? I would think the one on the drum track is using more since more audio is passing through it.

And for that matter, another question. Do plugins suck more juice the more you use the effect? i.e. if I've inserted an eq on a track and I'm sucking out say 9-10db of midrange, is that using more juice than if I were just shaving off 1 or 2 db?

Thanks in advance!

[daeron80]

It can differ from plug to plug. In my experience, for EQ, there is no difference between audio/no audio, nor does it use any more power when boosting/cutting a lot than a little/none. But then, EQs don't use much to start with. For some compressors, maybe a little more when actively working but not much more, if any. Some multi-band compressors might suck a little harder when all bands are actively compressing than when none are. A plug with a lot of detailed graphic motion in its window, such as those that include an FFT analyzer, will use more (graphics) power when the window open than when it's not.

Where you really get the difference is with VIs. A VI that is playing notes will use more CPU than one that doesn't, and every extra note being played at once generates a new instance of the instrument in RAM, thus taking lots more power.

[Shanegrla]

Ah yes, the VIs. That's where I probably should've started my example, as I use a lot of them.

So if I understand you right, if I'm playing a triad chord (3 notes at once) on a VI synth, it's using 3 times more power than if it were just a single note lead?

[daeron80]

Yep. Open the System Usage window and watch it while you play notes. Highly educational.

[Shanegrla]

Thanks again.