100% CPU Usage when mixdown

It happen starting cubase 12.0.30 till .40 update. Here is the video. I didnt load any single plugin/vst and the problem still occurs.

doesnt happen with cubase 11 .

windows 10 latest update
gpu latest driver update
chipset driver updated

ryzen 3700x
msi b450m mortar max


During the mix down phase this can happen. Because Cubase is claiming all resources to perform the mix down task by default to prevent issues like broken files.

And let’s be honest, what is it you would want to do on your computer while a mix down is in progress? Have you encountered any issues during recording or normal processing?

It seems to me you’re just looking for issues that don’t pose an issue in real live use?

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I feel like you are attacking me for no reason. What would I do while mixdown? browsing, play some mini games. extracting,compressing zip archive. the issue here why is it happening in Cubase 12, not in Cubase 11

If you didnt have any solution for this dont bother replying. Im not nit picking on this issue, this is really bugging me. It slow down my computer during this mixdown. I have a lot of 2-3 hours live mixing project to be mixdown and I want to use my computer during that time.

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Does the mixdown for the same project using exactly the same audio and rendering settings take less time in Cubase 12 than in Cubase 11?

If yes, I’d consider it a feature and not a bug.

Quite a few well written applications use 100% CPU if there’s a lot of work to be done. Video rendering and 7zip compression/decompression are a couple I can think of.

Also have a look at Studio Setup > Audio System > Advanced Options. There are some settings one can tweak.

Also, when you compare to Cubase 11, ensure that both versions have the same settings in there.

I’ve tried changing those settings the problem still remains. I have the same settings for both C11 and C12. And I’ve tried turning on Steinberg Audio Power Scheme.

I understand if the i use alot of VST/VSTI or whatnot if the cpu usage is high. But as you can see in the video, I didnt use anything on the mixer yet the mixdown process uses 100% CPU. This is a bug not a feature.


I’ve just tested rendering a section of a small project in Cubase 12.0.40 and didn’t see 100% CPU - usage. It topped out at just over 50% on my ancient i7-4930K.

I wish Cubase would use 100% at mixdown so export would be faster… but it doesn’t, it maxes out at around 50%. even with a completely empty project, it is max 40% here…
What it always does is max out one Core to 100%, that is the thread doing the most work, usually in a real project the one with the longest plugin chain and/or the most demanding plugins. All other threads get “synchronized” to that (which is understandable and works just like realtime playback).

Have you checked the Performance tab of task managr? Are really all cores you have fully maxed out?

yeap all core goes to 100% . I have tried reinstalled cubase 12.

I’m having the same problem.
I also tried mixing down an empty track and only C12 gets 100% CPU usage.
I reinstalled C12 and the situation remains the same.
I’ve been using Cubase for over ten years and this is the first time I’ve encountered this situation.


Yeah, but is the export faster on C12 faster, or is it the same?
More resources usually = faster render

Rendering is certainly fast, but it often overloads the CPU. The same project he mixes down on the C11 without overloading. I have a feeling that the C12’s CPU usage is the culprit.

Usually programs aim to 100% cpu utilization with tasks like audio export, it’s cpu-only, takes a lot of time and the system is pushed to get done with it as fast as possible.
In many cases 100% isn’t possible because of many reasons, like two logical cores sharing a single physical one due to hyperthreading and can’t run on full speed then interfering with each other. Also modern cpu’s have a bunch of independant pipelines for different low level tasks, some of them can be completely jammed with waiting instructions while others are idling.

Tl;dr: it’s complicated.

You can try to reduce the number of CPUs cubase is allowed to use in the task manager though (assuming you’re on win 10/11). Go to the details tab, or in processes tab right click on Cubase12.exe and choose “go to details”. There when you right click Cubase12.exe there should be something like “set affinity” (under priority). You can choose, which of your CPU cores your process can use, so if you remove 2 or 4 or something, you always have some free resources for other tasks.

Remember though: when your cpu has hyperthreading (it probably has) cpu 0+1 are the same physical core, as are for cpu 2+3, and so on. If you want a free physical core, deactivate them in pairs.


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This is a feature, not a bug, since it means Cubase has become better at using all of your computers’ resources to maximize parallelization and get the mixdown job done quicker (unless there’s a bug that eats up CPU for no reason).

If you have a need to wrangle your CPU utilization, Bitsum Lasso might be able to do what you need:

I’m not at home right now, but as far as I can remember, Cubase always used all my CPU on export. But even if, I can surf and do everything I want as long as its not heavy on the CPU and its a I7 8700k. Its maybe a bit slower, but it still works.

I would not say this is a C12 thing only though.

I have the same problem, I replaced the cpu with ryzen3900x and still the same problem. Some time during the mixdown there is an error: I have to restart cubase and pray to be more lucky (no with cubase11). This is a bug not a feature. I want to mention we paid a lot of money for this Cubase 12 and we are not at the first release…

I have the same problem, how can it be solved?

This thread is not about an error/crash bug during mixdown, but about the max CPU usage.
The max CPU usage during rendering can certainly be seen as a feature if it is done faster.

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It is not mixdown faster but in real time… I change the cpu (ryzen2700x with 3900x) but doing mixdown in real time the cpu usage is always 100%.

I tested it on my end here, and there is indeed an issue. The mixdown is about half the speed on C12 compared to C11 on top of that the CPU usage is maxed out as well, in C11 it was way lower.

I tested it on a project I am working on at the moment

On C11 it takes about 3 mins to export and CPU usage is around 35%
On C12 it takes nearly 6 mins to export and CPU usage is around 100% on all cores.

This is a serious isse:




I can confirm this. About to post the same thing.