It will consume a lot of power. With the 1120 Core frequency, some cards will work with -100 mV. That will save you 20% energy.
Thank you for suggestion
I actually put all values to default - but mining speed remains on the level of 32MHs
So will leave like that for couple of hours
The 390 is power hogger, I once metered it at 270w per GPU full speed (31-32MHs) and at 6 cards, almost 2000w (when dual mining), when I had to do a 2 x PSU setup (1300w x 2).
Although it was nice to get a monster rig at 185-190MHs but you sacrifice a PSU (which you could have used for 2nd rig) and drawing too much power from a 20A power point (dangerous). Keeping this setting this way will be too dangerous and will surely kill your PSU sooner or later.
With several good tips from Philip and other senior members, I settled for 5 x PSU design, with max underclocking and slight overclocking using Afterburner. I may sacrifice some MHs, but it keeps the rig investment safe and also prolong life of PSU and avoid shorting your whole house! Also, you can certainly get more MHs from 2 rigs with 1 PSU each (ie. 5 x 390 = 151MHs with 1600w PSU, times 2 = 302 MHs total for 2 identical rigs).
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