Due to changes to the Direct3D 9 files in the most recent Windows 10 April Creator's Update, OBS' Game Capture functions may suffer reduced performance. If you run into issues using Game Capture after the update, please follow these steps:
1) Download the updated files here:
https://obsproject.com/temp/get-graphics-offsets-win10-1803-signed.zip
2) Close OBS if it is currently running
3) Unzip the files to C:\Program Files (x86)\obs-studio\data\obs-plugins\win-capture, replacing the existing files
4) Re-launch OBS