Oppo hard drive

Hi everybody-
I'm on the cusp of buying either the Oppo 203 or 205. I have a Plex server running off of a decently powered laptop with a solid state hard drive for the OS and an external hard drive for file storage. When I attempt to play 4k video through Plex, I receive a message that my server is not powerful enough to stream the video. I'm wondering if anyone has had success with 4k video plugging a hard drive into the usb port of the Oppo. I'm assuming there wouldn't be a problem in doing this but I was just wondering if anyone had experience with it.