zaxxon,
we switch on cio or let oracle decide where to use cio because we want to avoid double buffering (what we have when both is on). If you switch off buffering completely (what you do with SETALL and cio both active) and you have a high transaction database, you are running the risk of saturating disks what used to happen in our company pretty frequently and slowed down the DBs more than not having anything activated.
But you are right - this is only true from Oracle 10g upwards - and we still do not know which DB version filosophizer is using
Kind regards
Nicki