I find internal HD more stable then External HD. My External HD in CFW for 3 times crashed, with black screens over the last weeks, one of the times it crashed while was saving the game state... the result? currupted data on save game, i had to start the game from zero. There are some games where you cannot backup the save data to USB PEN (Heavy rain) is one of them. I now backup the save directory with ftp server. So, with internal HD, with the same software (most recent software) i never had any problem... anyway, 120GB is not much, so i need a new one, but, i may need to keep the old one with different software, and i would like to know if sometime i will want to put the old HD if it will work, or if i will be forced to format it.