Yep, those power saving futures was a issue on certain games though, founded this on a forum though, donno if it works but people can give it a try for nvidia cards:
What you need to do is go into your Nvidia Control Panel and click Manage 3D settings, after that, add ShPSOBBw.exe. Set the area where it says "Select the preferred graphics processor for this program:" to High-performance NVIDIA processor. It'll run off the Nvidia card then.
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