The NAS, whilst it is feature rich, I've disabled everything other then full-disk encryption. The only thing running on it is Squeezebox: http://oinkzwurgl.org/ssods_intro
Edit: I see that these Pro QNAP versions are actually high-specced and high-priced Intel machines. The HP microservers still hit a sweet spot of low price and ECC ram though. QNAP must be making a bundle by effectively differentiating themselves in their software. Nothing in the hardware seems to justify the pricing.
It seems the newer generation has moved to Intel but still without AES-NI:
https://ssl.www8.hp.com/us/en/products/proliant-servers/prod...
It's not clear from what I've read if you can swap the processor out.
Why do you run FDE? How do you boot it?
See http://b3n.org/installed-xeon-e3-1230v2-in-gen8-hp-microserv... for info on how to do the chip upgrades in the current model.