I recently had to change my on-board drive controller from IDE mode to ACHI mode, due to a new SSD installed. Windows 8.1 was installed with IDE mode by default in BIOS and I had to make the change after this. After attempting to manual change the default set IDE mode to ACHI, in BIOS, I was unable to reboot into my Windows 8.1 install. After doing a small manual change within the Windows Registry, I was then able to change the on-board drive controller from IDE to ACHI and successfully booted to my newly installed Windows 8.1 environment. There seems to be a couple different ways to resolve this issue.
Although the Rise is a bit limited by it's internal hardware, I found that rooting this phone did improve performance as well as opening up various flexible options to other software apps, that would not have been possible otherwise.
The Rise does not support Custom ROMS, unfortunately, but there is some level of customization with apps such as ROM Toolbox, Pimp My Rom and Nova Launcher.