I have a 16GB Class 4 MicroSDHC Card from Sandisk. When I run the SD Card speed test on my Evo after the device has been on for a while, the write speed is listed as 1 or 2 MB/s and the read speed varies from 4 to 15MB/s. If I run the test immediately after rebooting the Evo, write speeds are listed in excess of 10MB/s and read speeds are around 14MB/s. It does not appear that I have any other programs using the memory card while the tests are running. Any thoughts on why the write/ read rate is so different in the two scenarios?