I also have noticed that cleaning is MUCH slower than before. I have the 3.20.1750 version. Win 7 home premium 32bit SP1, Intel Quad core 2 quad Q6600 at 2.4GHz, 4GB RAM. I am using simple 1 pass overwrite (as usual). It is taking 4 times as long as it used to for the same amount of cleaning.
what happened?