terrible CPU performance on Nuendo 5.5.6

We have upgraded our Nuendo installation from 4.3 to 5.5.6 recently and now the CPU performance on the Mac Pro is terrible. Even on idle Nuendo uses 10-15%. During the recording of one simple track it starts to use 20-40%. This produces jumps in the recording and also it is difficult to use our Contour Shuttle Pro precisely as it jumps between audio frames due to constant CPU usage.

We don’t use any plugins. Also this is a double Intel Quad Core machine. Did anyone see similar behaviour? We never had such issues with 4.3.

Nuendo 5.5.6 has worked very well for us on the Mac Pro towers, we’ve had no issues at all. There are many things to check, also make sure your graphics card is reasonably up to date.

Could you elaborate on what to check? I’ve already checked HDD, plugins, drivers.

Have you trashed your old Nuendo preferences?

That would be one of the first troubleshooting steps.


Yes I did. I’ve went throught all these folders https://www.steinberg.net/en/support/knowledgebase_new/show_details/kb_show/mac-os-x-how-do-i-uninstall-an-application-completely and couple of additional ones I could find. Deleted everything before installing new version. I’m not sure these instructions include everything though.

Geez… then, without further data, I’m stumped. I’m betting you’ve already checked to make sure your audio driver didn’t get changed in the update process, which is one thing I can think of that would cause this sort of thing. I’m even more sure that you’ll get scant consolation from knowing that I didn’t have any trouble with 5.5.6, including with my Contour Shuttle. Will keep thinking…


Chewy, did you run it under Mac OS X 10.5.8? Also what kind of Mac did you have? I’m running it on 2 x 2,8 Ghz Quad-Core Mac Pro.

It was so long ago… I don’t remember if I ran it under 10.5, but probably not. I generally run one OS behind current, so when 5.5.6 came out I was probably running 10.7 or .8.

I ran it (and am running N7 on the same computer) on a 3.2 quad core Mac Pro 3,1 with 16 G RAM.


OK, so we took another similar model MacPro and installed it from scratch. Installed Nuendo 5.5.6 and just after I fired it up it started to use 10-15% on idle. So this is not hardware problem or corrupted software/settings problem.

Any ideas how to debug this further? Does Steinberg provide paid support for Nuendo 5.5?


OK, so we took another similar model MacPro and installed it from scratch. Installed Nuendo 5.5.6 and just after I fired it up it started to use 10-15% on idle. So this is not hardware problem or corrupted software/settings problem.

Did the install include an OS install or just Nuendo?

You haven’t installed the Contour Shuttle Pro drivers have you? Eliminate as many variables as possible and start from a wiped drive, disable the usual MacOS junk, install your audio drivers, then Nuendo.

Where are you reading 10-15%, in Nuendo’s cpu meter or in Activity Monitor?

What era Mac Pros and what MacOS version? Two of ours have been on 10.8.5 forever and work very well with Nu 5.5.5 and 5.5.6.
What audio card?

I’m assuming you have latency settings set to something normal and not low.


The installation was done from scratch including the OS.

I did start Nuendo without any 3rd party drivers installed. The CPU usage I’m reading is from Activity Monitor.

The computers are MacPro3,1 (2008 I think) and it’s on Mac OS X 10.5.8 (we cannot upgrade).

We are using Yamaha AW2400 as an external audio card through mLAN fireware connection, however CPU load is present even without Yamaha connected. Another studio uses Tascam FW-1082 and it has the same issue.

Again we never had this problem with Nuendo 4.3. We upgraded to 5.5.6 because it is the last version which runs on Mac OS X 10.5.8 and it has CSV export for markers.

The CPU load would be not a big deal if the Jog/Shuttle would work normally. Now it sometimes jumps between frames even if operators uses frame-by-frame forward. Sometimes it’s worse, the audio just jumps during normal recording.


I don’t have any experience with the Yamaha, it’s required OS versions, or the stability of their drivers so I can’t comment. You said you had the issues with no third party drivers installed, good to know.

I don’t have any experience with that age of MacPro, ours are 2011 and 2012 models. We use OS10.8.5 with Nu5.5.x. You also have a much older graphics card which may or may not be causing problems. You can only run Nuendo in 32 bit mode on that Mac if I remember correctly, with large sessions you will run out of memory because Nuendo 5 caches high res waveform data in memory during record and it will crash. Speaking from experience…
If your sessions are large I highly recommend moving to a Mac and OS that can run 64bit due to Nuendo’s inability to NOT chew up large quantities of ram with waveform data. If your sessions are small then keep an eye on your memory use.

I don’t know what your priorities are, if the ShuttlePro drivers are not installed I wouldn’t worry about that working - there could be some incompatibilities. I personally would worry about getting the MacPro working first. You mentioned that in Activity Monitor you were seeing 10-15% when firing up Nuendo. Because Activity Monitor displays usage oddly I have to ask - is that 10-15% in the Nuendo row of Activity Monitor, or at the bottom under “User”? If it’s in the Nuendo row then it’s 10-15% of the total cpu percentage available unity-normalized to one core, which on your dual-quad machine is 800%. Apple Math.

I don’t remember what it is when we fire up Nuendo but if it’s 10-15% of 800% then you’re just fine at least to start. Your troubles are elsewhere. You mentioned “jumps in the recording” - that’s a significant problem. If the Activity Monitor percentages are as I mentioned (800% total) is it possible your ShuttlePro is causing the problems? If it’s activated during recording it can cause the timeline to attempt to jump to another location if the driver thinks something is happening.

So, I stated some stuff that may or may not be accurate based on my interpretation of your comments.

Good luck,

Respectfully, not so, Hugh. I’m running N7 on El Capitan on a 3,1 (all 64-bit), and it’s working great. Never had any trouble with the 5.5 versions, either.



Chewy you are correct, thanks for the correction. 1,1 and 2,1 are 32 bit only.

So if those 3,1 models can run 64 bit then you must have a mitigating factor why you say you can’t upgrade past os10.5.x. That OS is too old for us so I’m afraid I can’t help any further. OS10.8.5 with nuendo 5.5.x has been very solid for us.


I will try to look into Contour drivers however at the moment I’m afraid that’s a dead end. As I said, N4.3 never had this issue and it doesn’t show CPU load on idle, so I suspect that CPU load + spikes during the recording produces my issue.

Regarding upgradabiity of OS X, it’s a long story, which is related to PPC support, Xsan and other Apple incompatibilities.