Anyone
ahci has nothing to do with memory,its purely for hdd's/ssd's ect
if its booting up into windows with ahci mode enabled in bios then everything is fine
sorry i misread your post,if it blue screens at start up in ahci mode follow this guide
To resolve this issue, enable the AHCI driver in the registry before you change the SATA mode of the boot drive. To do this, follow these steps:
Exit all Windows-based programs.
Click Start, type regedit in the Start Search box, and then press ENTER.
If you receive the User Account Control dialog box, click Continue.
Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINESystemCurrentControlSetServicesMsahci
In the right pane, right-click Start in the Name column, and then click Modify.
In the Value data box, type 0, and then click OK.
On the File menu, click Exit to close Registry Editor.
After this you’ll have to restart your computer, go to BIOS and enable AHCI. When you log in to Windows again, you’ll notice the installation of drivers for AHCI. Another restart will be required to finish the driver installation.
or click this link to a reg file to save having to do above,just click it reboot into bios,set ahci,then save/reboot into windows n thats it
http://cdn.ithinkdiff.com/wp-content/uploads/2009/05/ahci.reg