Haven't seen it on here but if you are having issues with frame rate drop, fps dips and the like, going into the NVIDIA control panel and switching the setting in there worked properly for me so I just wanted to add this for those in the future.

Right click your desktop --> Select NVIDIA Control Panel --> Select "Manage 3D settings" --> Navigate in the Global Settings until you find "Thread Optimization" --> Select "Thread Optimization" and change it to "off." --> Select Apply --> Reboot Disgaea 2 PC.

Worked for me and now at a solid 60 fps. Good luck out there gamers.