Your welcome, by the way, on what motherboard did you enable it? i'm using Gigabyte GA-G33M-S2H (Intel® G33 + ICH9 Chipset) but i'm now facing one problem. the dvd-rom has some problem after i enabled AHCI. when i push the button, it opens and then close immediately (normally i have to push the button again to close it). and it couldn't recognize the disc until i restart the computer. i'm using LG H62N 18+/- SATA DVD RW Box. does anyone face the same problem and know how to solve it?? oops.... it was the cable connection problem. i reconnected them and the problem was solved. it was nothing to do with the AHCI setting. oh my god... i found out that it IS the AHCI problem. i re-connected the cables and the problem goes away and i thought it was solved. but eventually i found the problem just comes and goes under the AHCI mode. sometimes it appears and sometimes the drive works normally. but when i switch back to the IDE mode, it works PERFECTLY WELL. i've searched in the internet and found out that some SATA optical drives don't work well under the AHCI mode. some even disappear under the AHCI mode. but i'm thinking even the brand or the model number of the optical drive can't tell whether the problem would appear. i've read some posts that some people having the exact same model with me DO NOT have the problem. i'm not sure if it is just bad luck or certain models of optical drives plus certain models of motherboard together won't work well under AHCI mode. of course i hope to solve the problem and i'm trying to contact LG but the phone keeps ringing and no one picked up. i will try again very soon and hope to get an answer and hopefully a solution to the problem.