Why You Need AHCI Enabled For SSD
How To Check Whether AHCI Is Enabled Or Disabled

Open the Device Manager.
Expand the IDE ATA / ATAPI Controllers.

If you see AHCI Controller in the list, you have it enabled:
How to Enable AHCI On Windows 10 After Installing

If you have already installed and set up your Windows 10 with your SATA controller running IDE compatible mode don’t be upset! You can switch to AHCI in a few steps.

To be on the safe side, it is advised to back up your Windows 10 using AOMEI backupper before you start tweaking the registry.

Launch the registry editor (Win+R, type regedit, press Enter) and perform the following actions:

Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\iaStorV and set the value named Start to 0: iaStorV start 0
Find the key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\iaStorAV\StartOverride and set 0 to 0: iaStorV StartOverride 0 0
Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\storahci\ and  set Start to 0: storahci Start 0
And finally find the last key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\storahci\StartOverride\ and set 0 to 0: storahci StartOverride 0 0
Reboot your system.
Go to UEFI/BIOS and enable AHCI mode.

Enable AHCI Mode In Windows 7 Without Reinstalling

Launch the registry editor: regedit-win7
Navigate to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci

Set the Start value to 0:

enable AHCI mode without reinstalling Windows

Windows 7 msahci Start 0
Reboot your system.
Go to UEFI/BIOS during the reboot and change IDE to AHCI.