When running AHCI mode, those settings have to be change in the BIOS and the drivers installed during the initial install of the OS or a reformat of the hard drive. Generally this is only needed when using a RAID setup. Other wise your choices are SATA or IDE. If you don't have to much invested in the install, try a reinsall of the OS making sure to turn on AHCI mode in the BIOS or just wait until your ready or want to. In the mean time go into your BIOS and change it to SATA, you should see a speed increase.
Here's the thing - I can't even boot my old C drive in AHCI mode, using an external docking station. It will only boot in IDE mode but when I installed Windows 7 onto my old C drive, the BIOS was set to AHCI!
So Windows 7 won't boot in AHCI mode from my new C drive that's been re-imaged, or the old C drive, which means it's not the hard drives or the image.
So the question is - why won't Windows boot the C drive in AHCI mode after being unplugged from one SATA port & plugged into another? It makes no sense.
Turns out Window 7 wasn't booting from my old hard drive, I just thought it was cause I selected the external hard drive as the boot device in the BIOS but it was just booting the re-imaged C drive.
This always happens with microsoft, everything always turns into a ****ing headache. Before attempting the re-image, I read the microsoft help & support articles about re-imageing & there was nothing about AHCI. I'm ****ing over it & am going to re-install OS & start again - **** YOU MICROSOFT and all that **** you talk about Windows 7 being built for me.
Have you downloaded the AHCI drivers, those are seperate most of the time from the regular OS. Make sure you have those downloaded to a thumb drive, when installing double check BIOS are set to AHCI and when installing OS, it will ask for 3rd party drivers press F(what ever), then install AHCI driver from thumb drive. That should have you up and running. Good luck.
This issue was resolved by installing "Intel Rapid Storage Technology [v10.1.0.1008]", it seems that 3TB hard drives are not supported by "Intel Matrix Storage Manager Driver [v220.127.116.113]", which means I have to re-install Windows & discard the system image if I want to use 3TB hard drives. Because the re-imaged system won't boot in AHCI mode there is no way of installing "Intel Rapid Storage Technology [v10.1.0.1008]".