Track Count, RTAS and Buffer Size ...

[phobia]

Hi!
I was experimenting on using some number of plugins on roughly 6-9 test tracks on a G4 sawtooth 256 MB U-ATA 7200 drive.
Recording 24 Bit 48 Khz.

I used 128 samples as buffer size for recording and stayed on that level as I added effects.
A number of stereo DVerbs, EQ, and Stereo Comps.

Everything played back as it should. But, then I changed to a higher buffer size, 512 and 1024.

Suddenly I couldn't play back due to "CPU overload" message.

Why is that ? I thought having larger buffer sizes meant more processing for plugins ?

Or is it that higher buffer settings introduce more load on the CPU for IDE drives ?

Regards,
// Joakim W

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>>We need more time so that everything doesn't happen at once<<

[phobia]

Please also note:
When I changed back to 128 samples of buffer size, the session ran smoothly again.

// Joakim W

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>>We need more time so that everything doesn't happen at once<<

[Jeff D.]

phobia,

This has been observed by other G4 owners (including myself). My advice: leave the buffer at 128 and count your blessings!

If you search the older threads you will find more info about plug-in count vs buffer settings.

Good luck,

Jeff D.

[lwilliam]

Yep, I'm in the same boat. G4 and I get more plugins with 128 than 1024. Don't know why, but I'm not complaining.

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LW

[phobia]

Ok, has Digi had any explanations on these findings. It feels a bit worrying not knowing why your HW/SW doesn't behave the way you expect it to.

// Joakim W

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>>We need more time so that everything doesn't happen at once<<

[patchboy]

I was having the same phenomenon on my G4, but after doing several different types of projects, I have found a few circumstances when raising the buffer size improved my performance:

-A session with a lot of plug-ins (Waves and others) was creating pops in the audio at 128. Raising it to 256 solved the problem.

-Running PT alongside a virtual synth ruined the playback audio at 128. Raising the buffer to 512 not only cleared up the audio, but even allowed (turtle-like) metering while recording a track of the synth.

This is on my Yikes G4/350 w/256 Mb RAM. So it seems that when the system is actually against the wall, raising the buffer can create a little headroom. Otherwise, I just run at 128.

Hope this helps.

[phobia]

Well I guess I just stick to 128 samples as long as it will go.

I pity though if I really need some more power and raising tha buffer size gets the opposite effect.

Really would like to know why, just hate in when a piece of equipment behaves in a certain way I don't have control over.

Thanks,
// Joakim W

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>>We need more time so that everything doesn't happen at once<<