Want to Get new Headset. Do I need a separate AMP?

[DarkRacer]

I am currently thinking of getting the Sennheiser 350 Special Edition, but they have a resistance of 150. My motherboard is the MSI Z97 Gaming 5 which has its own on-board sound card with "audio boost 2". My question is, do I need to get a separate sound card to get the proper sound that these headphones should have or will the on-board sound card will be enough?

 

[hang-the-9]

If you read the first Amazon QnA it states that yes you should use an amp, but the 360 should not need one.