Can you make sure that you check the following:
1) Set the Maximum FPS in-game to something lower than the default, try 60 FPS instead of 150, or even lower (40)
2) Make sure your graphics drivers are up to date:
3) Edit the D3Prefs.txt file in your Diablo III folder in your Documents library, and make sure the following line reads like this:
Then test the game and see if it still happens in a Window
4) Check for overheating, I'm seeing a fair few posts here where temperatures are going over 100 degrees Celsius. This is way too high. Please ensure all fans are turning correctly and are dust free.
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