Glad you're booting in under 1:00 now! :thumbup:
No, I can't tell you exactly how the registry change vs a proper setup is different, unfortunately. I would have to do some intensive Googling which I can't atm.
The only thing that worries me is that you say when you try to install with the ACHI enabled, it crashes? That shouldn't happen. 
I'm no expert but usually, a "quick fix" is just a temporary solution. For example, if you want to set up an Unattended install of Windows XP, there are different ways to do it. You can open the WINNT.SIF and change the values- however this method does NOT create a WINNT batch file. Microsoft recommends using the SetupMgr tool in the Deploy.cab file, which creates both the .SIF and .BAT files.
See what I'm trying to say? A hack doesn't always correct everything. The recommended fix is always the best way if possible. I suppose one way you can verify is to check your Device Manager and at least make sure that Plug and Play assigned the proper drivers to your device. If the registry hack really works, then when you reboot the first time Windows should've detected a new device. Do you know if it detected the device and installed new drivers?
Lol, I guess I'm typing alot of stuff here.