Problem Description:
In the packaged standalone version (and when running as a separate process), there is a sudden spike in GPU memory usage—especially in shared GPU memory—during the game’s startup phase (i.e., during the black screen before the first frame is rendered). Once the game starts, the GPU memory usage quickly drops back to normal. This issue occurs in both Development and Shipping builds, but it is not observed when launching from the Editor.
Unrelated to Graphics Settings:
Adjustments to visual quality, Mip Bias (e.g., setting a global r.TextureMipBias=5), and enabling texture streaming do not resolve the sudden spike in GPU memory usage during startup.
Disabling Advanced Features Has No Effect:
Attempts to disable Nanite, Lumen, and Global Illumination have not solved the problem.
Version Comparison:
Although the engine version has not changed, earlier versions of the game did not exhibit this issue; it has only become apparent in recent versions.
Excluding Save System Impact:
Tests with an empty level as the startup map (with no additional content) still show the issue, which rules out the save system as a factor.
Solutions Tried:
Adjusting Mip Bias:
Setting r.TextureMipBias=5 was attempted to lower the mip level of high-resolution textures during initial loading.
Enabling Texture Streaming and Asynchronous Loading:
Texture streaming was enabled via r.TextureStreaming=True, and asynchronous loading (using FStreamableManager or the Async Load Asset node in Blueprints) was attempted to distribute the resource loading over multiple frames.
Disabling Advanced Rendering Features:
Nanite, Lumen, and Global Illumination were disabled, but the problem still persists.
Questions and Requests for Assistance:
Why does the startup phase in the standalone/packaged version exhibit such a large allocation in shared GPU memory, while this phenomenon is not observed when launching from the Editor?
Is this related to UE5’s full initialization of all rendering-related modules (such as Virtual Shadow Maps, Global Distance Fields, Shader Caches, etc.) during startup?
Is it possible to optimize the resource allocation during the startup phase—perhaps through delayed initialization or other methods—to avoid the instantaneous spike in GPU memory usage?
Has anyone else experienced similar issues, and are there any recommendations or suggestions?
Looking forward to your insights and guidance. Thank you!
If you combine the 3d graph with the memory usage you can see that the usage spikes with the 3d usage during the start of the game. It is most likely some form of resource binding taking place, pre-emptive setting up of texture addresses and pointers for gpu shaders etc.
I wouldn’t really be bothered with this, it’s not like the memory stays at a high level. It might even be some form of shader caching building the dervided data cache at the start.
Check if it repeats once your startup shaders are done compiling.
This problem is now very serious. My project only requires about 8GB of VRAM at runtime to run normally, but during the startup phase, the GPU memory demand suddenly spikes to around 18GB. This causes an “Out of video memory” error on mainstream platforms, especially on graphics cards with less than 8GB VRAM, preventing a successful launch.
Is there any way to limit the GPU memory usage during the startup process, even if it means a longer startup time? In addition to optimizing resource binding and asynchronous loading, is it possible to forcibly restrict the GPU memory usage during startup to avoid crashes caused by instantaneous over-allocation? Any advice or solutions would be greatly appreciated. Thank you!
Thank you for your suggestion! After switching the RHI to DX11, the issue no longer occurs. I also tried Vulkan and DX12 in both SM5 and SM6 modes, and the problem still persists. My current UE version is UE5.3.2. I’ll try upgrading the engine version and adjusting the lightmap resolutions to see if that further improves the memory usage situation.
I might found a solution. Many of the textures in my game are used in the UI, so their resolution aren’t power-of-two (for example, 1024×1024). As a result, Texture Streaming never streams them, and in DX12, the game ends up loading all of them at startup. After I normalized these textures, the issue was somewhat alleviated (although it still exists, it’s been mitigated considerably). Perhaps setting the compression settings specifically for UI might further help solve the problem.
Anyway,it can be a direction for solving the issue.
