High efficiency GPU mining - 3 MHash/J

[phelix]

 417W
-152W rig idle
+104W 4x Sapphire HD 5850 Xtreme idle (26W idle each)
----------------
=369W for four cards

phoenix: 1131 MHash/s

--> 3.06 MHash/s / W







How?

I undervolted the cards to 950mV and set the clocks to just before artefacts start to 666/222MHz. This can be accomplished easily with my program clocktweak (https://bitcointalk.org/index.php?topic=9982) for example.

Notes
The wattmeter is rather cheap and could be a bit off.
I always have a high stale rate of ~3-4% independent of this trick (maybe the WiFi connection).

At current difficulty/price it is still less profitable than mining at full speed, even with the rather high power costs here in Europe. But the rig runs more quietly and dissipates less heat.

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[dishwara]

You saying reducing or under volting gives same Mhash with less power used?

[Starlightbreaker]

your clocktweak can't really change the voltage of my cards though.
i dropped some of them to a lower voltage, still pulled the same wattage from the wall.

[dishwara]

I tried with -v 993, while i was running at 1175 @ 975/300 & changing it to -v 993, crashed the system.

[phelix]

your clocktweak can't really change the voltage of my cards though.
i dropped some of them to a lower voltage, still pulled the same wattage from the wall.

there are only a three voltages possible with my 5850s: 950mV, 1038mV and 1088mV

if I set them to anything else it will go the next higher possible voltage

[phelix]

You saying reducing or under volting gives same Mhash with less power used?

no you have to reduce core speed, too. to start you should set core clock really low like 500MHz. then increase the clockrate until things get unstable and go back 10% at least. I used the ati tray tools artefact scanner and increased by small steps. I got the first artefact at 670Mhz.

For a more stable system I should decrease the Mhz a little further but I thought mining at 666MHz at Eligius would be funny with the religous/atheistic discussions lately      Also 666/222 seems to be quite a hot spot.

[3phase]

Phelix, if I may humbly suggest that you try at least CGminer. It will reduce your command prompt windows to 1 and do the same thing that you're doing with equal Hashpower.

Other than that, really impressive performance. All those complaining about electricity costs, should at least have a look.

[PcChip]

I had to do something similar with a 5850 that I temporarily messed up the VRM heatsink on, I had to set it to either 1.000 or 1.038v (can't remember which) and it topped out at about 610 MHz I think (probably was 1.000v)

[phelix]

offtopic

Phelix, if I may humbly suggest that you try at least CGminer. It will reduce your command prompt windows to 1 and do the same thing that you're doing with equal Hashpower.

[...]

yes, I know. I have been thinking about getting CGminer going for a month now but was too busy doing other stuff like this experiment 

when the next fork comes I need to be ready with CGminer.

[BkkCoins]

I may be wrong but I don't think most people subtract out the idle rig consumption when calculating their MHash/J value.

I don't see why that would make sense unless you're calculating the difference between your normally-on system and what it uses when mining. But that doesn't transfer well to comparing with other users doing mining.

[phelix]

I may be wrong but I don't think most people subtract out the idle rig consumption when calculating their MHash/J value.

I don't see why that would make sense unless you're calculating the difference between your normally-on system and what it uses when mining. But that doesn't transfer well to comparing with other users doing mining.

they sure do for the mining hardware comparison list: https://en.bitcoin.it/wiki/Mining_hardware_comparison

how else could you compare cards from different systems? e.g. different number of cards, different cpu etc.

[phelix]

I wonder what the lowest voltage is you can run a GPU at. Has anyone ever tried a BIOS modification to undervolt below the BIOS level 0 voltage? Maybe it is possible to get even closer to the FPGAs.

[phelix]

3GHash/s in one rig - sweet

[m3sSh3aD]

Assuming I can find 4 or 8 to buy in a job lot...

...how much do these 5970 cards cost?

I've got a bunch of rigs that currently eat around 3 kW but space-consumption and heat output is starting to piss off the girlfriend. The benefits of being able to dry all the laundry at high speed by hanging it up in the 'mining bedroom' is being outweighed by the lack of space in the 'mining bedroom' to hang anything up.

So I'm looking at increasing the density of my rigs - swapping my collections of 5830s, 5850s and some 5770s (single slots... good for what they do) for half or a quarter the number of cards would be a Win. Especially if I could get 3 megahash/sec from one frame rig. Hell, I'm only getting 4.8 gigahash/sec from four rigs and 17 random GPUs.

Using 8 cards that have dual-GPUs would give more (better GPUs as well as nearly the same number of cores) - and would either be nice and spacious in two frame rigs, or with a bit of ingenuity, would pack into my mk3 rig (with serious attention to cooling).


However, I have the suspicion that one of these cards costs as much as the total cost of one of my rigs. Yeah, I could reuse logic boards, extenders, all that jazz... but I'd need HUGE new PSUs (expensive) along with the mega money cards.

Anyone here got an 'in-the-know' trade price for a 5970 in the UK? I know how much the online shops quote, and they're all out of stock so the prices are irrelevant. I wouldn't buy a GPU from eBay - too many stories of 'enthusiasts' going too far with overvolting and overclocking, permanently making the card unstable, then selling on eBay as a functional GPU. They take so damn long to diagnose as a real hardware failure (rather than a software config / BIOS / EFI problem) that I'm only interested in new parts, or unused parts.


I have the feeling I'm asking for the impossible. Am I? Should I stick to 5850s as and when I find reasonably priced ones?

Thanks for all helpful input!

iu payed 120GBP for 5850's, You wont find them that cheap now and 5870 that voltchange..... goood luck. EXPENSIVE. i get 410 m/hash with cgminer. Cgminer 2 IS AMAZING