I recently completed my first pc build and im so stoked. The only problem is since my case doesnt have an optical drive, I have to use a USB Flash drive to install windows 8.1. Which is fine by me, but when i go into the BIOS it gives me 3 different options for me USB drive. The regular usb drive then memoryPMAP and memory PMAP Partition 1. What are the differences? And which one do i select to install my Windows 8.1 OS?