time to upgrade is this a good motherboad for unraid ASRock Rack Mini ITX DDR3 1333 Motherboards C2550D4I thanks

 

Yes, that's an excellent board for a very power-efficient system.  You may, however, want to consider the even-better C2750D4I, which has 8 cores and has about 70% more CPU "horsepower".  The 2750 is a much better choice if you plan to do any Plex transcoding.

 

Note that while these Atom-based boards are excellent for a basic NAS with perhaps a single VM and a few Dockers;  if you plan on doing more extensive virtualization and/or a lot of simultaneous Plex transcodes, you should look at higher-performance boards that use a Xeon processor.