What is needed for Plex?

I would appreciate your expert advice here.
Thinking of replacing my home server, currently run a Lenovo TS140 with E3-1225 v3, 20Gb ECC and around 30Tb of 3.5" drives.
Used for video and music, photo storage, Blue Iris security cameras, etc.

Was thinking of a R710, then R510 for more bays, then R720xd, CPUs then range from X5675 to E5-2640 etc.

Can you advise on electricity consumption, compared to the TS140 that is around 100 watts, to each new CPU option?

Thanks for any advice,
John