Draw time getting worse with time

Hello,
In my application the draw times have periodic peaks (about 2 per seconds) and they get worse in time. After about 20 minutes they are so high that there is a visible stutter in the rendered scene.

My scene consists of 3 SceneCapture2D, each of them looking at a Niagara particle system. Every SceneCapture has its own system set as “show only actor”. They are set to not capture every frame, but a dedicated actor loops through them in its tick function and calls the method to capture the scene. The rendertargets are then used as images in a Widget placed on screen.

The default rendering process is blocked throug the cpp code

ViewportClient->bDisableWorldRendering = true;

My PC seems to be capable of rendering everything needed, the statitics show that the rendering occurs at about 100FPS.

Here is what I see when using the command “stat detailed”:

  • Frame: starts at 10ms, after 20 minutes it’s at 38ms
  • Game: 0.8ms
  • Draw: starts at 8ms, after 20 minutes it’s at 35ms
  • RHIT: 2.6ms
  • GPU Time: 8 to 9 ms
  • Mem: 1.25GB
  • VMem: 2.85GB
  • DynRes: Unsupported
  • Draws: 128
  • Prims: about 2450
  • TSR feed: 300 to 400 MP/s
  • TSR 1spp: 9 to 11 ms

If anybody has an hint on where to look for the cause of this, any help is appreciated.
Thank you!