WT causes the whole Windows animation to be super laggy (after RDP?), until all the WT processes are terminated

[fireattack]

Windows Terminal version

1.21.3231.0

Windows build number

10.0.19045.5247

Other Software

Command line

Steps to reproduce

There are no concrete steps to reproduce, as the issue occurs randomly. However, I’ve noticed two recurring patterns:

1. Using RDP to access this computer often triggers the bug later when I use the computer locally (though not always immediately).
2. Having multiple Windows Terminal (WT) windows open for an extended period.

Expected Behavior

It shouldn't cause Windows animation lagging issue.

Actual Behavior

I briefly mentioned this performance issue [in another ticket](#17414 (comment)), but I believe it deserves its own standalone discussion.

When the bug occurs, the entire Windows desktop UI becomes extremely laggy (e.g., dragging and switching windows), with performance dropping to what feels like less than 20 FPS. 3D applications like full-screen games are not affected; only the desktop UI.

To resolve the issue, I must close all open Windows Terminal windows (I typically keep 2–3 open at any given time). Doing so immediately restores normal performance.

The issue is not tied to any specific tab—I’ve tested this by opening a new window and then closing all existing windows, but the problem persists.

Here’s what the processes related to WT look like before I terminate them (and fix the issue):

[carlos-zamora]

Thanks for filing! What hardware (specifically GPU(s)) are you using /? Can you also update your drivers (if you haven't already) and share what versions are installed?

[fireattack]

Operating System
	Windows 10 Pro 64-bit
CPU
	Intel Core i5 14600K	36 °C
	Raptor Lake 10nm Technology
RAM
	32.0GB Unknown @ 2394MHz (40-40-40-77)
Motherboard
	Micro-Star International Co., Ltd. MAG B760M MORTAR II (MS-7E13) (U3E1)	36 °C
Graphics
	Intel UHD Graphics 770 (MSI)
	4091MB NVIDIA GeForce RTX 4060 Ti (MSI)	56 °C
	SLI Disabled

I use two monitors, one 2k 75hz and 1 4k 60hz

GPU driver info via nvidia-smi.

+-----------------------------------------------------------------------------------------+
| NVIDIA-SMI 566.36                 Driver Version: 566.36         CUDA Version: 12.7     |
|-----------------------------------------+------------------------+----------------------+
| GPU  Name                  Driver-Model | Bus-Id          Disp.A | Volatile Uncorr. ECC |
| Fan  Temp   Perf          Pwr:Usage/Cap |           Memory-Usage | GPU-Util  Compute M. |
|                                         |                        |               MIG M. |
|=========================================+========================+======================|
|   0  NVIDIA GeForce RTX 4060 Ti   WDDM  |   00000000:01:00.0  On |                  N/A |
|  0%   57C    P0             34W /  165W |    2832MiB /  16380MiB |      0%      Default |
|                                         |                        |                  N/A |
+-----------------------------------------+------------------------+----------------------+

(Please notice I use Studio Driver channel. So it might be slightly older than newest Game Ready Driver, but it is up-to-date:

)

[carlos-zamora]

Thanks! This is most likely something outside of our abilities, but you can try these things out:

1. set the window opacity to something below 100%. This causes composition via DWM and disables MPO. It can be found here:
   

2. set the graphics API to Direct2D. It can be found here:
   

Let us know if that helps 😊

[fireattack]

Sure, I will try if they help

[fireattack]

Unfortunately, changing graphics API to direct2D doesn't help. I will try the opacity trick next.

[fireattack]

Guys, I need some time to test and provide results.

Not sure why a week is considered enough time to label an ongoing issue as "no activity" and be closed.

[fireattack]

Setting opacity to 99% does not help, either.