Too much latency with HDN at 44.1

[Darryl Ramm]

Originally Posted by Matt Hepworth

Darryl, perhaps I'll try 13.

The thing is, my CPU (in PT) is literally at 2-4% on the test session with 24 tracks and two plugins.

No I would start at 7. Give your system an uninterrupted CPU for Pro Tools. Set %CPU to 99%, And leave them there while you try to tune other things. When you are totally stable then you can try increasing NCPU again. Stop looking at CPU meters for now.

And I do not see that you have actually posted any details on the CPU errors you are getting. What exact DAE errors?

Check all the installed plugins are up to date (not just the ones you are trying to use). You can also confirm you can track at low latency with no plugins instantiated at all, and then if you cannot then uninstall all third party plugins, and try again. Also try a new totally empty session (not from template) if that does not work.

[Darryl Ramm]

Originally Posted by Matt Hepworth

Using HDN in PT11, actually. Buffer of 32 gave me errors, so I couldn't tell how the latency was. At 64 the latency is too much.

You just have the tracks you are recording right? And the plugins you mentioned. No VIs or other things playing back as well?

Oh well, try to get 32 sample buffers running with no plugins in the monitoring path at all and see waht you get, etc. tryign all I mentioned above.

You absolutely have to optimize everything. No Blutooth, no WiFi, no wireless keyboard or mouse, not A/V software, no Spotlight indexing (turn it off on *all* drives for now). etc. etc. And just like with NCPU=7, leave all of these done no matter how annoying etc. while you counting other tuning/testing. Once you've found the best possible performance point yo can try backing off these things.

[Darryl Ramm]

This thread also seems to lack any information about your disk setup, exact make/model/rpm of drives, how they are attached if external and where audio/session files and any samples are stored. And are you using HD timeline cache? Actually a really clear description in one post of your whole system, Mac Pro model/date code. CPU specs and speed, memory, etc. and exact DAE errors you are getting would be great.

[Matt Hepworth]

Thank you for the advice. This is seeming like a lot of potentially fruitless efforts for downgrading to HDN.

I'll try some to see if I can get it stable at 32 long enough to see whether I can deal with the latency.

[Matt Hepworth]

I've tried with and without timeline cache.

System:

Mac Pro 5,1 (I think)

Dual Quad 2.66

16GB RAM

OS 10.8.3

PTHD 10.3.7, 11.0.2

HD3 Accel PCIx in Magma connected via PCIe

HD Native Core

I run no VI's. Dedicated audio drives are WD Caviar Black. I've also tried the sessions from my SSD.

[Darryl Ramm]

Originally Posted by Matt Hepworth

I've tried with and without timeline cache.

System:

Mac Pro 5,1 (I think)

Dual Quad 2.66

16GB RAM

OS 10.8.3

PTHD 10.3.7, 11.0.2

HD3 Accel PCIx in Magma connected via PCIe

HD Native Core

I run no VI's. Dedicated audio drives are WD Caviar Black. I've also tried the sessions from my SSD.

Great test, that should exclude any IO/disk related issue. Yes this can be really frustrating, but when pushing that low buffer the smallest possible thing can cause problems.

Is there any chance you can just live with LLM on the HDN setup?

[Matt Hepworth]

Not with any real projects, but for overdubs I have enough outboard everything.

[propower]

FWIW I suggest -

Use PT11
No Waves plugins (take Waveshell out of PI folder and put in unused one)
Hyperthreading (HT) = Off
Only Avid plug ins
Buffer = 32
See if that is a working starting place.
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This is my opinion but -- for low buffer work I have found speed trumps cores. Although your MP is an awesome machine its base clock frequency is not that high. I spent a long time trying to make a 2.6GHz i7 Mac mini do this work and it could not. When I switched to the 3.5GHz i7, huge difference.

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Note: the total difference in performance under the most demanding tasks you could do with HT on or off will be about 20%. Depending on the tasks that difference is often closer to zero. Don't let the marketing of HT fool you - it doesn't double your CPU just allows it to use any potential idle time a core has.

[nst7]

None of the computer issues would explain the latency though. If the computer was not powerful enough to run at a low buffer, he would just get stops and error messages, but the latency would not be increased. It either works or it doesn't.

I'm wondering if something else could be causing the delay, perhaps a plugin on the master buss?

I can definitely say this is not normal, but I can't explain why some people have trouble on their systems and others do not. I know Propower has had some difficulties also. On the other hand, I've been using a 64 buffer since my dual core Imac and 003 days, and always sounded like real time to me. Now with HD Native and my 5.1 Quad 2.8, it's even better.

[propower]

Originally Posted by nst7

None of the computer issues would explain the latency though. If the computer was not powerful enough to run at a low buffer, he would just get stops and error messages,

But this is what he said happens and because of it he can not run at 32. I suggested ways to address this and only commented as to if they didn't work clock speed may be a player.

WRT his perception of latency - can't it be that 44.1/64 may be too much for him? It is 2X the latency he is used to from TDM land?