I was really dissapointed with the performance of my 650 until i realized that games were only recognizing the integrated graphics system.
I tried deactivating the integrated card but the game (Falcon 4.0 BMS 4.32) wouldnt load.
Even when i deactivate the integrated card, dxdiag doesnt show the dedicated card (650M)
Ive tried a variety of things and im hoping that asking would help
Just like my laptop, that has a 640m, you have to go into the nvidia settings and specify which EXE uses the internal GPU, or the "high powered nvidia GPU"
I just set it to default on using the GT 640m for everything because I don't care about battery life, and that seems to work fine except for the random occasions where Steam, Skype, or even Google Chrome starts using the GPU to render instead... What a waste.