Y500 not performing as it should

There's something very wrong with my new laptop
I tried playing Crisis 3 and Dishonored on it. The first was a slide show and the second had a considerable input lag, both unplayable on lowest settings.
My version is with Intel® Core™ i7-3630QM Processor (6M Cache, 2.40 GHz), single GT650М and 8 GB of RAM
The video drivers are up to date, I have no idea what's going on.
I have two things that are a bit worrying - I use Win7 Professional instead of Ultimate and the second piece of 4GB RAM was additionally bought and placed (It shows the whole 8 GB in system properties). I know those two things shouldn't be the problem, but I'm running out of guesses.
Any idea what can be causing the issue?

 

Are you sure you are forcing your GT650m not integrated intel HD? Did you check with MSI afterburner which card are you using/clocks/temps?

 

Y500's Integrated graphics core is disabled. He couldn't use it if he wanted to.

I think the explanation is that when on battery, the GT650M's put themselves into a low-power mode.

Try gaming on the adapter?

 

I can't believe this actually worked. Thank you very much for pointing out the obvious, I can't begin to tell you how I was sure this is not the problem, but just to be sure I double checked and this was what was wrong... it
thanks

 

That moment when you realise your half-assed solution actually worked....