What will happen if I set my hard drive to run in AHCI mode?

[madindehead]

Just wondering, what will happen, if I set my SATA RAID/AHCI mode to AHCI with an operating system already on my hard drive?

Will it delete or affect my operating system in anyways?

I'm guessing AHCI is better than the default setting?

 

[rexehuk]

Need to change a registry value, reboot, change bios to AHCI then it should boot straight into windows.

 

[madindehead]

Need to change a registry value, reboot, change bios to AHCI then it should boot straight into windows.

Thanks mate. Do you know which registry value it is perhaps? Will I see any performance gains using AHCI?

Edit: Is this what I need to change here. I think this enables the AHCI driver, so now I should be able to change it in the BIOS, and it should boot fine?