The same problem as Flep had at the same situation: Windows 7 x64 was installed two weeks ago, Task Manager says that uTorrent takes 30-50 MB, but the total amount of memory in use is 3.6 GB (with 4 GB total in system). When uTorrent process ends, the amount of used memory is reduced to 1.7 GB (so system usually have in use after reboot). I don't know what it is, but it is obviously related to uTorrent. (Of course, the problem has appeared recently — with one of the last betas of 3.3.)