Support for Ultra High Speed MicroSD cards I am going to buy a new MicroSD card for my Motorola Milestone. The phone has Cyanogenmod 7. The upper limit as told by the manufacturer is 32GB, and because they got cheaper now, I'm going to buy the maximum possible. However, there are those new types of cards called “Ultra High Speed” which, I believe, weren't available when the phone came out.

Questions: Will those cards work with my device? Do they need any special support from the OS? Will I benefit from extra speed?
Will those cards work with my device?


Yes, I believe SDHC UHS-I (Ultra High Speed) cards are backwards compatible and will "work" in an SDHC only device (that the Motorola Milestone appears to be).


  Do they need any special support from the OS?


Yes, in order to operate at the advertised higher speeds. "Use of UHS requires that the host device command the card to drop from 3.3-volt to 1.8-volt operation and select the 4-bit transfer mode." Wikipedia - Secure Digital


  Will I benefit from extra speed?


No, it will work like an ordinary SDHC Class 10 card.