I've been away for a few days and so powered off the iMac. When I powered back up the machine and was checking out Activity Monitor to see how bad my Flash memory usage was, I noticed that kernel_task memory is now 1.17GB and rising. I upgraded the memory in my machine to 16GB and so there is no real worry about running out of ram but I am surprised it has got that high. Is this normal for an iMac? There are no apps running apart from uTorrent and Chrome at the moment. The iMac is a new 2011 model with an SSD installed.