Originally posted by BlakeShellman I tried the three different SD cards I have. All are SDHC. I changed everything back yo the default and they were still slow. Better...but still slow.
Class 10 cards are recommended. However the 'class' system is now outdated and as far as I know has not be updated to represent current speeds. Class 10 was supposed to be 10MB/s. However, most new cards will be available at speeds of 45MB/s or even 95MB/s. Do you need those speeds for the k-5? No, however they will make sure you max out whatever speed the k-5 has and will future proof you if you move to a faster camera at some point. They also will work faster in your computer, especially if you have a USB 3.0 reader.
Also, make sure you check the firmware version, there was an update that improved card speed compatibility with faster cards.
Sandisk Extreme Pro cards are what I use, 95MB/s.