Extreme lag when Unreal Engine is open (SOLVED)

Hi all,

I have same problem - everything was OK till I upgrade UE to version 4.2. No it’s lag like hell. I have GeForce GT650M and I using laptop Alienware MX14.
I update drivers but still same problem and also check if I using high-performance and not second intel graphic card. I using win 7 64bit.

What can be problem? anybody knows…

Thank you