Cameramemoryspeed.com found that while the E-M5II's card controller does not support the fastest speeds of the UHS-I cards (like the Sandisk 95mb/s card I have been using) it does support and takes full advantage of the newer UHS-II cards. It appears to be the first in the OM-D line to do so. http://www.cameramemoryspeed.com/olympus-e-m5-ii/sd-card-comparison/ The Lexar "1000x" UHS-II cards seem to be the sweet spot right now for less money than the fastest UHS-I cards and with almost twice the write speed in the E-M5II. Buffer clearing times are halved from the UHS-1 cards and in Sequential L mode (RAW) the E-M5II can continue to shoot at 4.7 fps even when the buffer is full! I have ordered the 1000x 64MB version for $36.99 and will keep my "slower" Sandisk UHS-1 card for a backup.