If you compare our g-cards here...
http://www.notebookcheck.net/Mobile-...ist.844.0.html
...you'll see that your 460M is significant slower even though it's a fairly new card.
On top of that I've overclocked mine which gives me apx. 2000 more points.
And then my CPU is faster but more important has four cores.
I'd say those are the reasons.