Four drives in a RAID 5 array will increase the reading and writing speed and boost the overall performance of the NAS system. It’s okay to start with a small number, but you need to ensure you’ll be able to upgrade later. Hard Drive Bays: The number of drive bays is essential.Around 4GB should be acceptable, but more RAM is recommended. RAM: If you’re using NAS for Plex only to stream, you won’t need much RAM.Aside from the streaming quality and the number of streams, you’ll need to consider which type of media files you’ll play (MKV, MP4, WMV) before you decide on the NAS CPU. You’ll need a powerful NAS CPU if you want to stream in 4K. CPU Power: Determines the resolution of streaming and the number of streams you can run.Your streaming experience will heavily depend on the quality of that hardware. You need to consider several things when buying a NAS for your Plex server.