Since you have enought HDD space left I recommend trying a couple of other things to try to prevent freezing. I recommend not using wireless to play BF3, instead plug your console directly into the router for the fastest connect. Also turn off the PS3 media server as it takes up console resources and other people can log into the console to play media on it while you are playing causing performance issues. One additional thing that you can do is to not use quick match and only use the server browser to find games inside of your own region. Playing outside of your region can lead to lags and freezing as well.