Hi everyone!
I keep running into hitches in my project packaged in Unreal Engine 5.8.3 while in true fullscreen mode (even in a clean Third Person Template project).
PC specs:
Processor: 13th Gen Intel(R) Core™ i9-13900K 3.00 GHz
Windows 10
3 monitors at 75Hz (I only tested the game on one of them)
Things I tested that didn’t work:
r.D3D12.UseAllowTearing=1
Nvidia Control Panel:
Disable fullscreen optimizations
Note: These spikes/hitches occur even when I’m just standing still.
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ChenDong
October 6, 2026, 10:45am
3
Your CPU profile already shows the hitch is not a game-thread spike. IDXGIOutput::WaitForVBlank_NoBusyWait is about 96 ms of the 148 ms CPU frame, and D3D12_Present is almost the same. That is the swap chain waiting on a vblank while the GPU is idle, which is what you get when the game is fullscreen on a display that is not the one the engine is presenting to, or when the frame rate and the monitor are fighting.
You are on Windows 10 with three monitors at 75 Hz and you only tested on one of them. Try r.D3D12.AllowFullscreenMode=1 and r.D3D12.AllowTearing=1 together, and also r.D3D12.UseAllowTearing=1 which you already tried alone. Without both fullscreen mode and tearing, Present still waits for vblank even if the game is rendering faster than 75 fps. In the NVIDIA control panel, set the game to the specific monitor (not “auto-select”), and set VSync to off for that monitor, not Fast. Fast vsync still inserts a wait when the engine presents on the wrong output.
Also set r.VSync=0 and rhi.SyncSlackMS=0, and make sure the packaged game is not using the editor’s windowed mode. In Project Settings, Engine > General Settings, set Default Window Mode to Fullscreen and Default Window Width/Height to the resolution you actually want, so it does not fullscreen onto a different display. If the hitch disappears when you run the packaged build with only one monitor enabled, it is the multi-monitor present path, not Lumen or Nanite. The GPU numbers in that same capture are under 0.5 ms on the GPU and 1.5 ms on the CPU, so those console variables that zero out streaming and occlusion are not the cause of these spikes.
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Thank you for your reply!
Vsync is already disabled in both Unreal Engine and the Nvidia Control Panel.
I tested with a single monitor (I disconnected the other two), but the result was the same.
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