The DS713 you are considering is impressive and far more than I need or care to spend. But it's pretty nice.
Personally i would love if i could go lower end, but the streaming of 8 cameras on a lower end cpu wont cut it, or at least thats what synology represntative said. I have DS111 that i wanted to use, and it supports 8 cameras from synology specs, but not full hd, so idk really even if the atom will cut it, but thats as good as it gets on synology without going into the super expensive setups. Personally i haven't bought it yet, as im still deciding if i should just go with another PC build, i have G3220 + H81i + Gskill Snipper 8gb + wd 3tb red + picoPSU 90W XLP with a 80W brick that should power a small setup fine, only missing a case, so im researching open source software to manage the cameras to see if i could do something viable.... but still researching, i still would like to try the synology, but will see.
Oh, and I forgot to add to my original post I am going to use 2, 3TB WD Reds. I am getting it initially to just round up all of my data scattered across HDD drives that are accessed individually in a drive dock, a multitude of flash drives, DVDs/CDs that are not backed up. I don't keep everything so even if I RAID it, I should be fine. (That's yet another decision). The price difference between the 3TB versus the 4TB can be applied to an external drive for another backup layer. Then after that a HDD stored off site.
HDD will come down in the next 5 months, WD had 5tb for December, but delayed, i think it should come up before mid year, so that should push the 3tb to $100, 4tb to $130, where the 4tb will be imo a better buy. Seagate also has 6tb version (enteprise on release) that will come out this year, if the consumer come later should also push down pricing of the 3/4 tbs.
Your list will be very handy. Btw, I checked the fan mod link and the Noctua NF-B9 fan is still available. "Drop in, plug and play. Perfect fit. No system error alarms as it operates as OEM on the same voltage as the Y.S. Tech fan". http://forum.synology.com/enu/viewtopic ... 40&t=45825
Any reason it's not on your list? SSO-Bearing, Rotational Speed (+/- 10%) 1600 RPM, Airflow 64.3 m³/h, Acoustical Noise 17,6 dB(A)
Well i do like noctua and use them in 2 setups atm, i personally just think they are overpriced, i do use them as their PWM fan range is still imo the best in the market allowing you (if you can control them that low) to end up with a very quiet setup, but the sound signature imo there are better fans out there for less money.
The NF-B9 seems like a decent choice, specially since its closer to the rpms of the orignial TY Tech (although other things might be different), personally i wouldn't go here on noctua because there is no PWM need, and for 3pin i prefer either of the ones on the list, specially because i would like a more quiet setup, just have my doubts into how low the synology undervolts it and how either of the 4 fans i posted go and if they will not tick, etc.
I think the Noiseblocker seems a good bet to me, 1300rpms still seems on the high side to me but its lower than Nexus, Noctua and the TY Tech, but can work on 5V (according to noiseblocker, not sure if its true). Im not planning a dual hdd setup so there will be less heat inside, i wont be doing any raiding so there will be less CPU need, but the 8 cameras might load the cpu some... still got a research more, but its hard not many do it, and the ones that do almost never post on forums, so im kinda on my own atm.
Nexus on the other hand is probably the best choice, since SPCR review it
(although might be different with the black n white version that its sold now) and still is on the recommend fan list
, from the review its starting voltage is 2.4V, so it should be fine to whatever the synology throws at it.
If i end up chosing the DS713+, ill probably buy both the noiseblocker and nexus, and ill post some graphs on FanXpert2 into their behavior and min/max rpms. If nither works out, in terms of noise, then i might try the Scythe 1000rpm, but with undervolting it might be too little airflow for the small heatsink the DS713 has on atom 2700.
So after several days of intense Google searches and research I am going to go with the DS214. Hopefully it will sit far enough away. If not, once I get it I can look at how hard changing the fan would be.
Good luck, hope it works out for you. Be sure if you have time to share how noisy it was, and if you do the mod on the fan please post what you use and how it vary the temperatures and noise.