When you use the Magnifier app on a remote Windows 10-based computer through a Remote Desktop Protocol (RDP) session, the CPU usage of the dwm.exe process spikes.
This issue occurs when smoothing is enabled in Magnifier. This feature is enabled by default in Windows 10.
This issue occurs because RDP uses the software renderer. The software renderer uses the CPU to run graphics commands.
To improve performance, disable smoothing in the Magnifier app. To do this, open the Settings app, select Ease of Access, select Magnifier, and then clear the Smooth edges of images and text check box.