Data and logs on different physical drives - advantage?

["Weber, Johann (ISS Kassel)" <jweber@xxxxxxx>]

I learned for other database systems, that it is an advantage to have database on one physical drive and transaction logs on a different physical drive, as this should minimize seeks on the hard-disks.

 

Is this true for PostgreSQL (V 8.0 on ReadHat)? My tests do not show any speed gained when placing pg_clog and pg_xlog on a different drive.