Windows 7: AHCI Question

Guys/Galls

I had an interesting situation pop up about 2 hours ago....
I was reformating my machine and have been using AHCI for the past few months.
After my Network install was finished and it did its reboot to setup windows, My machine failed to post.
It was sticking on AHCI Drive one detect...
(No HDDs hve been connected or disconnectd)
I reset my Bios same thing....
I undo ALL my sata devices and rebooted and I posted.
I got into my bios and reset my drives to IDE mode.
Reconnected everything and it proceeded to finish install as it should.
With me being me I had to find out why...
I rewired my case, cause I found a strained sata power cord.
Still no luck after about thirty minues of testing the drives and different configs, I found it was the drive I installed onto.
I booted back into my Bios with that drive unplugged and set back to IDE.
Plugged the drive back up, and booted back to my network installer and deleted all partions.
I set my drived back to AHCI and Viola everything worked correctly.

What could have cause this???

Just that strained or slightly loose sata cable would be enough, I've seen certain sata cables cause problems while other work fine.

Crazy thing is the actual sata cables were fine... I thought the same thing at first but the connections were fine... Im getting a new drive just to be safe though.