I encrypted my V10 after about 3months of use. 64GB SD card installed as well. Took less than an hour -- be sure you are plugged in. Every restart prompts for encryption passcode. You get 30 tries -- I've never needed more than two. Don't notice any slowdown after boot, boot may be a bit slower (~1 minute from power on to usable phone -- which is really kinda amazing that we all just accept this now. I'm old enough to remember pushing an ON button on a device like a TV and it was on and usable in one second. Sigh.)