Choosing a fast SDHC-card for a NX10

Hi. I have owned a Samsung NX10 since launch. Being a n00b at the time I made the mistake of buying the cheapest class 2 SDHC card I could find. I shoot only RAW.
Now I'm looking for a faster card to bring the write times down.

My question is:

• What should the specs of the card be? - the write/read times, etc. 30mb/s

I guess that there should be a point where a faster card does not result in faster write times due to hardware limitations of the camera.

I remember there was somebody who posted the result of a test based on the NX10 and different cards. Can't seem to find it via search.

Finally, does the camera support the new UHS-I standard?

Thanks!