Yes... Setting your controller to AHCI should have enabled TRIM support in Windows 7.
You can follow these steps to verify it is enabled:How to Verify TRIM is Enabled
In the start menu search box, type" cmd";
Right click the cmd program and select Run as Adminstrator; and
In the command line type "fsutil behavior query DisableDeleteNotify".
If DisableDeleteNotify = 0 TRIM is Enabled.
If DisableDeleteNotify = 1 TRIM is Disabled.
When typing in the command window, don't include " " when typing.Source