Re: NAS hardware recommendations

[zloster]

On 12.12.2020 19:26, Pierre Neidhardt wrote:
> Hi zloster!
>
> Thanks for the detailed report and the resourceful links! :)
>
> After some investigation, I think I'll go for one of the ASRock.
> I could find them at the following price:
>
> - ASRock J3455-ITX: 98€
> - ASRock J4105-ITX: 100€
> - ASRock J5005-ITX: 120€
> - ASRock J5040-ITX: 150€
>
> I'll go for the cheapest option.
> No the j3455 and the j4105 are basically the same, the main difference
> being memory.
>
> j3455 has SO-DIMM 204 pins (DDR3)
> j4105 has SO-DIMM 260 pins (DDR4)
>
> Any recommendation regarding memory?  Has DDR3L a lower power consumption?
DDR4 has lower standard voltage than DDR3(L)*.
DDR4 - 1,2 V
DDR3 - 1,5 V
DDR3L - 1,35 V
*for the standard transfer speeds - 2400 MT (megatransfers?!) for DDR4, 
1600 MT for DDR3(L).

Some examples:
https://www.servethehome.com/ddr4-dimms-system-power-consumption-tested/
27 Watts less after removing 12 modules with 8GB DDR4 RAM
27/12 = 2,25 Watts per module

https://www.tomshardware.com/reviews/intel-core-i7-5960x-haswell-e-cpu,3918-13.html
Power Consumption: Crucial DDR4-2133
32 GB (Four Modules)    11.85 W
16 GB (Two Modules)    5.94 W
8 GB (One Module)    2.98 W
4 GB (Rated)    1.49 W
For the other speeds the data is similar.

https://www.micron.com/-/media/client/global/documents/products/technical-note/dram/tn4007_ddr4_power_calculation.pdf
Very comprehensive writing about memory consumption. I've also found 
some other research on the topic but it is on another computer and I'm 
too lazy to search for it again. Basically the research said that the 
Micron model gives very conservative (i.e. big numbers, gives higher 
consumption than normal) but it all depends on how busy is the memory bus.
> For the rest, I'll just get a second hand computer for 30-50€ that has a
> 4GB of RAM, so I can get the whole thing to run on 130-150€.  In that
> sense, it's cheaper than any NAS I can find on the market! :)
This calculation is valid if you don't factor in the electricity prices. 
In most places the electricity is relatively expensive.
0,3 kWatts (i.e. 300 Watt system) * 12 hours (1/2 day) = 3,6 kWh

i.e. 3,6 * 2 = consumption for 24 hours.

For UK:
7,2 kWh * 0,144 GBP (average price of electricity in UK) = 1,0368 GBP 
per day (1,0368 GBP is 1,14 EUR using the today exchange rate).
https://powercompare.co.uk/electricity-prices/

So for a systems running 24/7 there is good reason to search and pay for 
the lowest consumption per given performance need.


Best regards,
zloster