Quote from: drakoin on January 07, 2014, 04:02:53 AM

Inspired by these peculiar settings ...

Quote from: mine2mind112 on January 05, 2014, 08:20:47 AM

I suggest try value like these.... power usage is about 180W x card.
GPU 1: 625.1 Kh/s | I:13
58.0 C F: 51% E: 915 MHz M: 960 Mhz V: 0.981V

... I have searched for sweet spots in completely new places. And found one in an unexpected area!

Usually, the optimal khash appeared around engineclock/memclock = 0.62 to 0.64.
But now I have found a new one, at memclock/engineclock = 1.06, that is more engineclock than memclock (!).
It has less khash, but so much less Watt that it's worth it.

It's the third (C) in this before-and-after table:

	CC	MC	Volt	Celsius	khash	Watt	khash/watt
(A)	907	1450	1.175	74	622	277	2.25
(B)	1025	1635	1.038	73	692	240	2.88
(C)	854	799	0.893	70	578	153	3.78

(A) = before undervolting (before I started this thread)
(B) = best undervolting (stable > 39 hours)
(C) = best undervolting & underclocking (stable for many days now)

3.78 instead of 2.88 is pretty amazing.

Yes, compared to the max possible hashing performance, I loose out on 16% hashrate - that is like throwing away 38 euros worth of 229 euros hardware; but on the other hand, the new settings (C) are saving 36% electricity compared to the max hashing performance (B), and 45% of electricity compared to before-the-undervolting (C).

This new sweet spot is cool:
Mem clock slightly lower than engine clock, for an XFX 7970!!

People in Solomon, Virgin, Turks, Caicos and Marshall Islands, Tonga, Jamaica, Niue, Denmark, Samoa, Tuvalu, Germany, Philippines, Cook Islands, Brazil, Kiribati, Belgium, Netherlands, Italy, Ireland and Sweden - we are the good ones, because our governments actually care about the environment *g*. But here's a way for us, to also participate in cryptomining - we have to undervolt and underclock our coinmining rigs dramatically.

Kiss

thanks for this post in particular, and this thread. i've got an XFX 795A TDFC and i had a mare getting it to work properly. your post about using VBE7 to edit the BIOS boot state as that allows you to unlock the voltage was helpful, as my card was running toooo hot; then these odd settings with the memclock lower than the engine clock helped more. the card is now producing a few less kh/s but at a much lower wattage and heat. good thread!