Using Dual Card Slots of K-3 Means Half Writing Speed (i.e., 2X Slower)

See this quick test:

http://www.pentaxfans.net/thread-144953-1-1.html
(in Traditional Chinese, Google English translation here.)

The two SD cards used by that K-3 owner is a high-speed Sandisk Extreme SDHC UHS-I 32GB, both are of the same model and identical.