Isaac Sim Not Responding When Switching Windows, GPU Usage Drops to 0%

Omniverse Isaac Sim
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Isaac Sim Version

5.1.0
5.0.0
4.5.0
4.2.0
4.1.0
4.0.0
4.5.0
2023.1.1
2023.1.0-hotfix.1
Other (please specify):

Operating System

Ubuntu 24.04
Ubuntu 22.04
Ubuntu 20.04
Windows 11
Windows 10
Other (please specify):

GPU Information

  • Model: NVIDIA GeForce RTX 4060 8GB
  • Driver Version: 580.95.05

Other Specs

OS: Ubuntu 22.04.5 LTS x86_64
Host: 21J8 Lenovo ThinkBook 16p Gen 4
Kernel: 6.8.0-85-generic
Uptime: 6 hours, 4 mins
Packages: 3532 (dpkg), 13 (snap)
Shell: bash 5.1.16
Resolution: 2560x1600
DE: GNOME 42.9
WM: Mutter
WM Theme: Adwaita
Theme: Yaru-prussiangreen-dark [GTK2/3]
Icons: Windows-Eleven [GTK2/3]
Terminal: gnome-terminal
CPU: 13th Gen Intel i7-13700H (20) @ 4.800GHz
GPU: Intel Device a7a0
GPU: NVIDIA 01:00.0 NVIDIA Corporation Device 28e0
Memory: 10211MiB / 31881MiB

Topic Description

Detailed Description

While working with Isaac Sim, when the Isaac Sim window is the active window, everything works fine and GPU usage is stable and normal. However, when the mouse cursor is moved to another window and interacted with (even just scrolling for a few seconds), the GPU usage of Isaac Sim suddenly drops to 0%. Shortly after, the application becomes unresponsive, showing a “Not Responding” warning. I have to force quit the application.

Steps to Reproduce

  1. Open Isaac Sim and use it normally (active window).
  2. Move the cursor to another application window.
  3. Scroll or interact with that window for a brief moment.
  4. Observe GPU usage drop and Isaac Sim freeze behavior.

Error Messages

text

[Warning] [carb] Client gpu.foundation.plugin has acquired [gpu::unstable::IMemoryBudgetManagerFactory v0.1] 100 times. Consider accessing this interface with carb::getCachedInterface() (Performance warning)

Screenshots or Videos

image_2025-10-27_141523103
image_2025-10-27_1415231031920×1263 145 KB

Additional Information

What I’ve Tried

  • Updated NVIDIA drivers to the latest version.
  • Updated Isaac Sim and extensions to the latest versions.
  • Disabled some non-essential extensions to reduce load.
  • Optimized system resources and closed unnecessary background applications.

Related Issues

(None known currently, but open to suggestions or links to similar reports.)

Additional Context

The issue appears to be triggered by losing focus on the Isaac Sim window and interacting with other UI windows, which impacts GPU usage and stability. Any guidance on how to prevent the GPU usage drop or resolve this freezing issue would be greatly appreciated.

kit_20251027_135714.log (6.1 MB)

Edit: added computer specs and log file

2

Your GPU (NVIDIA GeForce RTX 4060 8GB) is below the minimum requirement listed for Isaac Sim 5.1.0 —NVIDIA’s documentation recommends RTX 4080 (16GB VRAM) and higher for supported operation in complex scenes. While it’s possible to run Isaac Sim with lower VRAM (like the 4060 8GB), stability and performance issues may occur, especially with heavier workloads or high memory scenes.

  • Have you tested this issue with the Isaac Sim 5.1.0 GA release, and does it also happen with earlier versions such as 5.0.0?
  • Are simpler demo scenes (low GPU/VRAM load) also causing the application to freeze when switching windows, or only complex scenes?
3

I have tested both 5.0 and 5.1, and the issue occurs with both versions. I have only tested the physics scene and ground plane, but the problem persists regardless. While running my scene, it operates smoothly without any lag or freezing issues—until I switch my active window. What confuses me even more is that there is plenty of empty space in both my RAM and VRAM. I also don’t believe this is related to the minimum requirements, as my simulations run flawlessly while it is active window since I start the isaac sim otherwise.

4

Could you please try launching Isaac Sim with the --reset-user option to see if this resolves the issue? Additionally, to help us investigate further, could you verify whether this problem also occurs with the included demo scenes? If possible, please provide a detailed list of reproduction steps and, if you’re able, attach a screenshot or video of the behavior.

5

i am just another user and am also curious whether switching renderers do anything on your end. for example, switching from real-time to interactive (path tracing).

6

I noticed that the issue only occurs when working on my scene. I opened the Nova Carter Robotics example, worked around in it, and everything functioned properly without any issues related to this problem. I plan to investigate further and will share more details about the issue. Could you guide me on how to enable verbose logging? Additionally, if any specific information is required, please let me know and provide instructions on how to obtain it.

I also attempted to launch using the --reset-user command, but nothing changed; the issue persists. Lastly, I would like to ask about the “detailed list of reproduction steps,” as I didn’t quite understand what it means.

here is the issue video:

EDIT: issue happens while working on other sim examples. And I noticed it happens also when I tried to run ros2.

7

I did not noticed any effects

8

Thank you for sharing your screencast videos—they’re very helpful for understanding the issue.

Could you please confirm whether you encounter the same “Not Responding” and GPU usage drop symptoms when testing with the Isaac Sim 5.1.0 GA release and official demo scenes?
Additionally, to help us assess whether this is a regression, did you observe this problem in earlier versions (like 4.5.0), or has it appeared only in more recent releases?

9

I tried the Isaac Sim 5.1.0 GA release and initially noticed no changes. Frustrated, I discarded the entire project, recreated my robot and environment from scratch, and this approach resolved the issue. The “Not Responding” popups stopped appearing. I suspect the problem arose because I initially created the project in version 5.0 and modified some attributes, which likely caused the issue. However, one thing I still don’t understand is why Isaac Sim displayed the “Not Responding” popup and the GPU usage dropped to 0, even when running a working demo scene. Anyway, everything is functioning properly now.

Edit: It did not work. The issue persists. This time, I tried closing using the window’s close button and then clicked “Save & Close.” However, after restarting Isaac Sim, the same problem continues to occur.I also added a clock publisher and applied the QoS graph simultaneously, so I’m unsure which one is relevant.

Edit2: I observed something interesting. When the program freezes and GPU usage drops to 0%, moving the window causes it to resume running. Here’s the video.

10

To help us investigate further, could you please provide a step-by-step list describing exactly how you reproduce the issue?

A detailed sequence helps us attempt to reproduce the problem locally and look for patterns in the freeze behavior.

If you have example files or videos showing the steps, those are also very useful.

Thanks for your help—this information will make it much easier for our team to troubleshoot!

11

Hello!

We noticed that this topic hasn’t received any recent responses, so we are closing it for now to help keep the forum organized.

If you’re still experiencing this issue or have additional questions, please feel free to create a new topic with updated details. When doing so, we recommend mentioning or linking to this original topic in your new post—this helps provide context and makes it easier for others to assist you.

Thank you for being part of the NVIDIA Isaac Sim community.

Best regards,
The NVIDIA Isaac Sim Forum Team