I started the new snapshot with the new launcher and noticed my FPS being horribly low (5 instead of the normal 40), After some testing I found out that minecraft was using the intergrated graphicscard instead of my nvidia card.

So it apears to be the case that the new launcher is the reason behind this all. I don't know if mojang can fix this, however the previous lancher never had this problem (so it should be possible).

obviously you can put the launcher in the list of programs to execute with the high-end graphicscard but not everyone might know this.