after copying files from sd card to internal with ES File Explorer, the phone became extremely sluggish and semi-frozen, and was not able to recover without pulling the battery. I tried to copy no more than 100MB of files at a time. then it acted like the cpu was running at 5mhz. with 250mb ram free, I figure I can copy files ? no? also seems ES file explorer becomes slow as f%$@ when viewing the root directory.