If you do not have the ACTUAL (desktop) GPU, that can explain things. A normal laptop downgrade of performance for a normal desktop to laptop adaptation has always been in the range of 15% all the way up to a 30% reduction from the desktop level. But since nVIDIA chose another route, the difference is far too frequently 100% because the "Optimus" simply doesn't work, and the game refuses to work with the Intel IGP that is the only video that runs.
If it's really a desktop after all, you've plugged your display cable into the wrong port!
