The change is needed in the operating system kernel mode graphics driver. Microsoft is looking into scheduling this development. In the meantime, provided you have purchased a platform allowing you to, the workaround is to disable the low end GPU so Windows uses the only one left. Today, Windows will always use the POST graphics card.litmol commented
I'm having a similar problem – a significant drop in fps and lags after Windows 10 anniversary update. When connecting an external LCD via docking stations with the latest Displaylink driver installed (8.0 m3) fps drop down significantly. Without the external LCD, or when it's connected directly to my laptop, fps is great and there are no lags, so there is nothing wrong with my Nvidia GTX 960M video card.