WORKSTATION/HOME SERVER/NAS = 2 PCs?

While investigating how to upgrade our home computing nervous cell, my non gaming multimedia workstation that also served as the home media file server, hours of reading finally made me realize that today, with more than 10 TB of data, it may be time to split the 2 functions into 2 machines:

#1. NAS or better file server for managing large amounts of datas (films, photos, medias, personal documents) 24/7 with low power consumption.

#2. Computing power for multimedia (video/photo/sound) editing, encoding for specific momentum uses (no more 24/7 power on).

RESULTS : 2 computers instead of 1?

Today's best CPU+Motherboard+RAM is only 2x faster than 5 years ago for the same power consumption (70-130W).

Latest Intel i7 3770K CPU + 8-16GB DDR3 RAM + Motherboard cost about 400€ today for 'only' 2x the encoding and overall speed of my actual Intel Q6600 Quad Core CPU + 4GB DDR2 RAM.

HD4000, the GPU (Graphic Processor Unit) of Intel i7 Ivy Bridge is very similar in performance to my actual cheap 2 year old passive graphic card HD5450. I am stunned it is no better. Power consumptions of the 2 GPUs are almost the same @idle and @100%.

Overall, 400€ seem expensive for an upgrade from which there is no hope to gain much power economy nor more than just a few minutes on heavy tasks like encoding that can run by night anyway. I may not upgrade before the gain/cost appears much more worth it.

#1 A power-wise more efficient 24/7 NAS/homeserver seems to maybe offer more perspective of evolution and gain/cost advantages.

There are several options so I will investigate that.

This http://www.willudesign.com/BlackDwarfTop.html very much looks like my dream tool. Am I alone?