Motherboard asrock Asrock 970 Extreme4 vs 990E4

[carly200]

Hi,

i am not completely new to bitcoin, but have left over a year ago due to personal reasons. Now I am back and overwelmed with what has happened in the meantime.
Now I need advice on Hardware for BTC/LTC (mainly LTC) mining that gives best Hash/Watt since I live in Europe and pay ~0.27€/Kwh (yeah, green energy^^) LOL
(don't tell me that I will pay more in electricity than I will gain; I know that might happen most likely)


I plan on starting with a single 7950 (saphire vapor x) and see how things work out. maybe adding 1-3 of the same later if i am satisfied
(8GB Ram, Semperon 145, ~1000W Platinum PSU)

I stumbeled across asrock mainboards, mainly the 970e4 as a recomendation, but whats the main difference to the 990?


Which hardware gives me the best Hash/Watt
How is the spacing on the mainboards; do i really need risers? is would prefer an "almost" closed from the rig casing.


What ist the power consumed by the mainboard? I figure that the 7950s may be around 200-250W
any help/advice in undervolting? optimizing for Hash/Watt?



Any comments? Help?

cheers.

[carly200]

I came across some info that sapphire 7950 vapor-x have the voltage locked. does that mean that they don't work well for undervolting? or was that just a tempory (software update) thing?

[carly200]

small update:

maybe the 7950 vapor-x is only voltage locked on one of its two bioses. can anyone confirm?

Another question: do boost models come with higher factory voltage? that would be bad for my undervolting idea...

[bitcoin44me]

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