Recently I have noticed that when Hearthstone is in Windowed Mode my FPS drops by half and just performs terribly.
I get a constant 144fps in Fullscreen but Window it varies from 60-77fps.
I have tried:
Disabling all overlays.
Turned off V-Sync in Nvidia Control panel.
Editing the Options.txt with vsync=0 and targetedframes=144
Re-installing, repairing, and deleting the appdata folder.
Disconnecting Second monitor.
Reducing Desktop Refresh rate to 60.
Disabling Full Screen Enhancements.
Enabling High DPI mode.
So what is causing Hearthstone to essentially run at V-Sync level of Frames when Windowed?