Yes you should change it to ahci, also make sure you try a different usb drive. I remember i have 2 usb drives. 1 is from sandisk which works with every linux distro out there and i have 1 from mediarange (if i remember the brand right) and that one refuses to boot with linux on some machines.
Edit: Yep its a MediaRange USB Stick, USB 3.0, 64 GB, Zilver. I don't recommend that stick for linux installation.
This one works great SanDisk Ultra Flair USB 3.0 Flash Drive - 16GB



