Originally posted by bobmaxja No it's not compatible . Here what they say on the latest Firmware upgrade for SXDC card but the comment is for all SDHC
That just means the K-5 does not have the UHS-I 4-bit transfer mode, which allows up to 104MB/s.
Standard 1-bit transfer mode allows up to 25 MB/s - but many cards fall short of this theoretical transfer speed.
It will be interesting if the Extreme Pro gets closer to the theoretical limit compared to the Extreme. There's a lot more to the performance of a memory card than just the bus transfer speed.