My fresh Kubuntu 12.10 installation often (but not always) "blocks" when doing things like "sudo apt-get update" and often spends several minutes on "Reading package lists". Other things that take unusally long is the linking stage after compiling programs.

My setup and symptoms are similar as the ones in this thread.
I have a Dell Precision M4700, with one SSD and one HDD. Root is mounted on the SSD, and /home and /var are mounted on the HDD. I have /tmp mounted as tmpfs.

Any suggestions?