I just purchased the entry level Synology DS413j to use for my HTPC media storage. It is running DSM 4.2 3211 The Synology specs state that in HDD hibernation mode, the DS413j should use 7.68 watts. From my testing using an Arlec 240v power meter with just a single 3TB Western Red WD30EFRX installed, the Synology was reading 15w when running, and 11w after HDD hibernation kicked in due to 20 minute disk inactivity. I’m a little annoyed that it is not performing at the advertised 7.68 watts – that is about $6 per year in energy at my tariff of 21.351 cents/kWH. I imagine in order to get that value, Synology must have stripped the NAS down to the bare services required.
The DS413 model supposedly can do full system hibernation and drop to 3.37w. If your NAS will 99% of the time be idle, but powered on 24x7, and assuming the 21.351 cents/kWH tariff value from above, you are looking at $6.30 per year to run the DS413 at 3.37w versus $20.57 for the DS413J at 11w:
DS413J with only HDD hibernation –> 365 days per year * 24 hours per day * .011 KW * .21351 $/kWH (Origin Energy) = $20.57 per year to run.
DS413 with system hibernation –> 365 days per year * 24 hours per day * .00337 KW * .21351 $/kWH (Origin Energy) = $6.30 per year to run.
Thus, I could save $14 in a year, by purchasing the DS413 over the DS413J.
DS413j = $365 ; DS413 = $519. (519 – 365) / 14 = 11. It would take 11 years for the DS413 to pay for itself on energy savings assuming I never use the NAS :)
If on the other hand, you are actively using the NAS 24x7 and fully loaded with 4 disks, you are looking at around 35w for both DS413 and DS413J.
365 days per year * 24 hours per day * .035 KW * .21351 $/kWH (Origin Energy) = $65.46 per year to run.