Realtime export -> CPU spikes and errors

Hello there,

I am using Nuendo 7.1.2 on a Mac Pro (2x 3,06 GHz and 64 GB Ram), RME Fireface 800 and outboard Lexicon PCM96-Reverb. Everything is synchronized by a wordclock (Rosendahl Nanosyncs) in 44.1 KHz.

I would like to use the Lexicon as external hardware reverb and I am sucessful doing so during playback an mixing.
But when it comes down to exporting (in realtime) a multitrack project (12 tracks) with the Lexicon on the Main output, I run into constant breakups caused by CPU-problems.

I do not use extensive plugin-work, since I am mixing classical musc: EQ here and there, some Multiband-Compression and the outboard reverb by Lexicon.

What I tried:

  • Disabling “Asio Guard”
  • Disabling Apples “Spotlight” (read about that somewhere)
  • increasing the buffer size of my Fireface 800
  • Reducing the bitrate of the export to 16 bit only.

—> Still not one sucessful export so far!

Is there any new information considering the realtime export in Nuendo and the CPU-problems caused by that?

Thank you so much in advance and have a grat day!


This also happens on OSX 10.8.5 with Nuendo version 6, same specifications otherwise.
Opened a new session. No plugins, just the external reverb, one audio track…. CPU-error…

ASIO guard is turned off. Buffer is set to 512.

Any help?

Thank you very much

additional information:

In Wavelab 9: No problem! Same computer, same interface, same software plugins, same external hardware.

I can´t help but think that this could be a Nuendo-problem.
Is there anyone who could help, please?

Thanky you

Hi Philoton,

I use to have the same problem .Plays okay but when I tried to export , spikes all over the place. My problem was a bad HDD and solved buying a new one. The only thing that solved partially the problem was consolidating all the parts that had the spikes. Even if you are not hearing the problems on playback, try consolidating only the audio parts where the spikes are. It worked for me.



Thank you, rbesser!
Since the external effect (Lexicon PCM96) on the main out seems to be causing the CPU-errors on realtime export, I do not know how to export single parts only, sorry. The reverb has to be there, not on single tracks…

As I said, We are talking about ca. 6 audio-tracks with eq only routed to the main stereo out. There we have an external Lexicon for reverb and that´s it. My computer or harddrive does not seem to be the problem, since Wavelab does not produce the spikes (although only one stereo track instead of 6 single tracks, but still)…

Any other thoughts?