I was browsing around the forums and look what I came across
To change memory timings on Asus A7M266 use the following :
In BIOS setup select "Advanced" then "CHIP Configuration"
then change SDRAM Configuration from "By SPD" ( which uses an
EEPROM on the DIMM to get the recommended settings for the next three parameters ) to "User Define"
When set to User Define, you may then amend the following three parameters:
CAS Latency : change from 2.5T to 2T
RAS Precharge time: change from 3T to 2T
RAS to CAS Delay: change from 3T to 2T
If you have any stability problems then reset
SDRAM Configuration to "By SPD"
This will cause your memory timings to be returned to those recommended by the DIMM manufacturer as stored in EEPROM on the DIMM.
Beer is the devil's piss.