Phoronix takes a look at the Ubuntu 9.04 Home Encryption Performance

One of the exciting features that is being worked on for Ubuntu 9.04 is encrypted home directories. What this means is that at install-time for either the LiveCD or server installation (or at a point later on when creating additional user accounts), the administrator can opt to have the user's home directory encrypted. This is a step-down from the Ubuntu 7.10 install-time encryption that would encrypt the entire hard drive and just not the user's home directory, but alas, that comes with performance consequences. At the request of Canonical, we have carried out a few benchmarks showing what effect the Ubuntu 9.04 home encryption feature has on the system's overall performance.

Ubuntu 9.04 Home Encryption Performance