Cubase 15.0.20 GUI lag when MixConsole is opened as detached window

[Thomas_Jankowski]

System

Windows 11 Pro 25H2
AMD Ryzen 9 7950X
64 GB DDR5 RAM
NVIDIA RTX 4090

Steps to reproduce

1. Launch Cubase 15.0.20 on Windows 11.

2. Create or open an empty project with no tracks.

3. Open the Project window only.

4. Open MixConsole in the Lower Zone.

5. Observe that the GUI remains smooth.

6. Open MixConsole as a detached floating window.

7. Observe that the GUI becomes noticeably laggy.

Additional observations

• The issue is reproducible even in an empty project.

• Reducing the visible MixConsole racks does not improve the lag.

• The Performance window can also trigger visible lag.

• SuperVision and VocalChain can trigger similar lag when visible.

• Many other plug-ins do not trigger the problem.

• Static windows such as Audio Connections do not trigger the same issue.

• The issue happens with one or two displays.

• Usual Windows and NVIDIA graphics-related adjustments did not solve it.

• Cubase 14 on the same machine did not show this behavior.

Expected result

MixConsole should remain smooth whether it is displayed in the Lower Zone or as a detached window.

Actual result

MixConsole is smooth in the Lower Zone, but becomes laggy as a detached window, even in an empty project.

[steve]

How to format a bug report

Hello all, If you would like to report a bug in Cubase for other users to confirm, please start a new topic in the with the tag ‘issue’ please follow these easy rules: Before you post a new report, use the search function to see if it was already reported. You might find a solution, or a report waiting to be confirmed. In that case, reply to the post. It is not necessary to post multiple reports in separate topics One report should include one bug. The topic title should be a brief de…

[Martin.Jirsak]

Hi and welcome to the forum,

Do you use HiDPI screen? If you have multiple screens, does it happen on all screens?

As you are using Nvidia, please try this:

• Download the latest Studio driver version from here. If there is no Studio driver for your graphic card, use the one, which is available and continue with the same steps below.
• Disconnect the computer from the Internet to ensure Windows will not download and install its graphic driver.
• Uninstall the NVIDIA driver.
• Restart the computer.
• Start the NVIDIA driver installation (as administrator).
• Don’t install the whole package, use the Custom (Advanced) settings.
• Disable everything (don’t install NVIDIA Experience, PhysX, etc.), and keep the video driver enabled.
• Connect your computer to the internet.

[KT66]

I cannot confirm this. I only use the mixer as a separate window and it never displays this characteristic. The gui remains responsive and fast.

Windows 11 25H2, Cubase Pro / Nuendo 15.0.20.

[Thomas_Jankowski]

UPDATE – I think I may have found a very specific trigger.

First of all, mea culpa. I have been chasing this issue for months and I focused so much on the detached MixConsole / second-screen / NVIDIA side of things that I completely overlooked something very simple in my own layout.

I had the Audio Performance Meter displayed in several places at the same time:

• in the Project window top toolbar,
• in the lower Transport Panel,
• and in the MixConsole toolbar.

What I am seeing now, at least on my system, is this:

• One or two visible Audio Performance Meters: GUI feels normal and precise.
• As soon as a third Audio Performance Meter is visibly displayed on screen, Cubase 15 becomes noticeably laggy from a GUI point of view. Moving/editing events becomes less precise and feels delayed.
• Removing one of the visible meters immediately brings back the normal fluidity.
• It seems to be about meters actually displayed on screen. A meter in a hidden area/window does not appear to have the same effect.
• Opening the detached MixConsole or the Audio Performance window had made me think that those windows themselves were the problem. In reality, they may simply have been adding another continuously refreshed performance display to an already crowded layout.

The important part: I do not reproduce this behaviour in Cubase 14 with the same computer, project, display configuration and general workflow.

So I am not claiming that I have proven a Cubase bug yet, but this now looks much more like a Cubase 15 GUI/performance-meter refresh issue than a general GPU, monitor, plug-in or audio-engine performance problem.

For context, before finding this, I had already spent a lot of time testing the usual suspects. This was not a case of immediately blaming Cubase without checking the system:

• tested with one monitor only and with the second monitor completely disconnected;
• tried several NVIDIA driver versions/installations, always Studio drivers;
• tested NVIDIA settings including G-SYNC behaviour and fixed refresh for Cubase;
• tested Windows HAGS on/off;
• tested MPO disabled/restored;
• disabled Xbox Game DVR / capture features and the NVIDIA overlay;
• launched Cubase in Safe Mode with program preferences disabled;
• reset the graphics driver;
• tested ASIO-Guard disabled;
• monitored GPU/memory activity while reproducing the issue: no obvious resource saturation;
• all of those tests produced exactly the same behaviour.

None of the above made a meaningful difference.

For me, this is not a critical issue anymore because I simply do not need three copies of the Audio Performance Meter visible at once. Keeping only one or two visible meters gives me the normal smooth workflow again.

Still, it would be very interesting to know whether anyone else can reproduce this in Cubase 15:

1. Show the Audio Performance Meter in the Project toolbar and in the Transport Panel.
2. Add a third visible instance in the MixConsole toolbar, or open the Audio Performance window.
3. Try precise event/block editing in the Project window.
4. Remove one visible meter and compare.

Does anyone else see a noticeable GUI slowdown only once more than two visible Audio Performance Meters are displayed?

Sorry again for initially describing this mainly as a detached-MixConsole / monitor issue. I had been trying to solve it for months and simply had not noticed that I had enabled the same meter everywhere in my layout.