An i3 in terms of raw CPU power isn't going to break any record there either. The important bit is to have a CPU that supports Intel's QuickSync technology. That means a Celeron might potentially be able to do just as good a job as an i3.
Beyond that, you are going to end up paying the price of a desktop PC just to get an i5-based NAS - not worth the money. Either get an actual server, or get an Atom or Celeron-based NAS, and put something like a Zotac PC next to it to host the Plex server. The total cost of such a solution will probably be less than that of an i5 or i7-based NAS.
I would have to disagree. The i3 will walk circles around the Celeron. You have low end CPU's like the Atom, Celeron etc...then you have the higher end CPU's like the i3, i5, and i7.
To compare a Celeron to the "i" series is not practical. They are in two completely different leagues. I own several NAS's with different CPU's and know from real world experience that the weaker CPU's can not and will not handle the demands of what the "i" series can. The Quad Core Celeron 2.0GHz (J1900) is a great CPU for its respected capabilities, but it's still limited.
Think of it as a little 4 cylinder with variable valve timing. You get a lot of HP per liter, but no matter how how great it is (even if it was turboed / over clocked) you're still not going to be able to pull the boat on the trailer due to the lack of torque. The QuickSync technology is the variable valve timing. It's great...I like it....but my point is, there is a limit to how far even the J1900 can go.
Granted, most people don't need anything beyond the J1900 as it'll do a fine job for basic needs. But for those who want performance and the torque to be able to haul something without it kicking the bucket, a 4 cylinder even with variable valve timing and/or force induction will not be able to pull the weight. This is the point that I'm trying to get across about these CPU's.
Having a NAS is much more than having the ability to just transcode, although that is a big part of most peoples needs. Sure the Celeron based J1900 can get the job done, but anything beyond that the 4 banger will kick the bucket with heavy simultaneous loads. VM's, Multiple On the Fly 1080p/Original File streaming, etc...forget it...the lower end CPU's can barely handle one 1080p/original file on the fly transcoding (okay maybe 2 or even 3 which is a stretch)...try adding 5+, with VM and other stuff going on...It 'ain't' going to happen.
This is why going with the lower end (although still pretty peppy for it being a Pentium 3.2GHz Dual Core - G3250) QNAP TVS-X71 NAS and running that until you need to upgrade (to an Intel i5-4590S or i7-4790S) makes more sense than buying a weaker NAS now and having to buy another NAS in the near future.
As a side note, even the Intel 3.2GHz Dual Core (G3250) Pentium is a better choice than the Celeron 2.0GHz Quad Core in the performance category. Sure the G3250 will utilize its CPU more for the tasks that the J1900 would with using its QuickSync technology, but that is specific to the function of transcoding. In every other category except power consumption, the G3250 stomps the J1900 by at least double or triple. It is what it is.
Upgrading your CPU is much more cost efficient and makes more sense all around as the TVS line with its 10GBe capability makes it very future proof.
. Now I'm researching the HDDs. The last 4 or 5 HDD I've bought, were WD Black series, only one failed in warranty, the rest are still running ok. Now I was taking a look rather to Hitachi than WD. I have as a backup a Seagate (an external HDD) but that is acting strange, some times is working, some times it doesn't.
