The flash chips inside the USB Flash Drive are typically slower than an HDD. Also Nintendont has issues with some Flash Drives that why HDDs are recommended. I myself use a USB SDHX Reader with a Polaroid 64GB SDXC in it and haven't had a problem yet. Many cheap no name brand USB Flash drives just don't work with Nintendont.I have a 128g miniature flash drive. They're faster than hard drives, since there are no disks being read. One thing to be aware is flash drives are less reliable than hdds so if I were you I'd still keep a 2nd backup. Also, mine doesn't get hot in the Wii, which is great for a flash drive's life cycle.