I use Geforce 630M.
I don't want to use bumblebee, because it is unstable for me.
It will suddenly freeze my ubuntu 12.04 64 bits.
How to do that?
If your BIOS has option to disable optimus functionality only then you can use the nvidia driver.
else there is no way you can turnoff intel and work with nvidia because the images generated by the nvidia GPU are transported & displayed through intel card.
You can try with primus. It work with bumblebee but improves performance at large. Because it doesn't use virtualgl (which was intended for remote connection and involves compression etc).
In conjuction you can use nvidia-experimental driver which is told to be double the performance for new graphics card.