Low FPS on Minecraft with a 675MX

I’m new to the forum. I tried to find similar problem to mine but I’m quite sure my case is particular.

I have a MSI laptop and I manged to upgrade the CPU and the GPU from an Intel i5-460M and an Nvidia 460m to a Intel i7-720qm to an Nvidia 675mx.

Let’s skip the part in which you ask if everything works fine, it does.
After the routine checks I tested the card with some games:
Kingdom of Amalur, emulated with Wine, was about 25~30fps with the older card, now 50~60.
Unigine Heaven gave me a score of about 500 with Ultra Quality and Extreme tessellation, 20 to 40 FPS.
This means the new card IS working.

But Minecraft dropped from 30~40 FPS with the 460m to 9~15 with the 675MX.
I also noticed a slightly performance drop in Guild Wars 2 emulated with wine (though in Windows it fly in about 50 FPS).
Actually I don’t other have games to test but I will test more meanwhile.

I’ve read the Keplers have a bug in which the Core Speed is reported badly but the mhz is set correctly… specifically nvidia-settings report 324Mhz for all the three speeds but it should be 324, about 450 and about 653Mhz (I’ve got these values with Afterburner in Windows).
Can it be related?

I don’t really know what to do… should I add the nvidia-bug-report log?
Any clues?

EDIT: Solved. I though there was some regression but it was another problem: Minecraft is crappy.
I guess it’s the same for Guild Wars 2. It is strange the other card was faster on linux.
Is there anyway to change the post title to mark this post as solved?