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I am running 5 7950s, Gigabyte WF3 with the f43 undervolted bios and the rig is using 1475 watts at the wall.  I just purchased a kill-a-watt meter and am in disbelief.  I have flashed the f43 bios to the cards, so the voltage of the cards is now 1.09 volts.  That is like 300W per card!!!!!  This seems way to high.  I have read these cards are supposed to be using less than 200W per card.  Any suggestions?

card seting 1050core  1250 ram   1.050v   630kh per card  3 cards 705w  4 card 920w

reaper setings

protocol litecoin

worksize 256

aggression 20
threads_per_gpu 1
sharethreads 18
lookup_gap 2
gpu_thread_concurrency 20992

Now calculate for 80% PSU efficiency and knock off about 200W for the motherboard, CPU, drives etc..... .... ...

was that to me ? if so thats what i pull from the wall

i have a 43 wat cpu, laptop hdd, and my PSU is an 80plus gold efficient PSU...so i understand i need to knock off some for mobo and psu inefficiency but it should not be that drastic



Are you using the same card?  Gigabyte WF3 with f43 bios?

i am using saphire vapor x cards but the setings should work the neer the same

+1 depending on what psu and cpu he is running could be less.

I am running a 55w CPU and my power supply is 80 plus gold efficient.

I get roughly the same when running a z77a-GD55 + G1610 + 5x7950 Gigabyte WF3 (1100/1400mem). Most of the time however, I'm probably around  ~50-90 watts lower (that you stated)  probably attributed to:

1. I run dual gold PSU's so the efficiency is close to peak rated.
2. I run them cool < 70C so with fan RPMS ~1800-2000RPM. This might improve longevity, but since I have to use dual box fans forcing air through the rig, that costs another 100W combined.

Try to compute if the additional power is worth it (if it matters that is). I live in an area where power is relatively cheap, however, the power bill is still substantial.  :(

That is almost my rig exactly.  I am running a z77a-gd65 and 5 WF3 (1100/1400)  I have one box fan blowing air over the cards.  They run at around 70c.  I am using a gold rated 1300w PSU.  I think our numbers should be much much lower.  I unplugged one card and am getting a reading of 1170 which means that 1 card is using almost 300w.  Thats crazy.

That sounds about right dude

200+ per card, plus the mobo/cpu/ram

+ 10%+/- loss in PSU efficiency.

Plus monitor, router, cable modem, printer, keyboard, mouse, fans, beer cooler :D, etc and whatever else may or may not be plugged in

I run 4 at less than 1000 watts so not sure why people are saying this is normal.

Just curious, at what voltage, core and memory clock? Thanks.

On my rig with 4 x 7950 Vapor-x when mining scrypt power consumption from wall is around 980W. Cards are on stock voltage in range from 1.06 to 1.12. They run stable at 630 KH/s.

gigabyte triple fan cards are voltage locked, period. no amount of bios flashes or editing will change that. unless you have the multimeter or kill-a-watt pictures to prove me wrong, this is what you will need to deal with when messing with voltage locked gpus and overclocking with scrypt.

I run 6 x 7970 on each computer, powered by only a 1300w psu. They are all pure reference and I can change the volts to whatever I want. They hum along like any other day, no problems

Mining Litecoins (or any other scrypt) uses WAY more power than SHA256.  My machine uses 200W more at the wall when doing LTC compared to BTC.  So, some people may be comparing apples to oranges here.

i have 4 7950s scrypt 2,500kh+ 913w frowm the wall including monator

7950 do have good hash to watt ratio... but you got to lower your hash rate.

best i could do is 5 * 580khash for just over 1000watts

soon as i go over 600 khash it can EASILY go over 250watts each card.

your power consumption is about right but if you really want to save on power you have to shave off the hash rates.

if only btc diff was lower because i was doing 5 * 550 mhash for 840 watts!!!

sucks to pay 27c/kw

Not exactly. For Gigabyte 7950 WF3s (AFAIK):

1. The original rev 1.0 boards are not voltage locked.
2. The official bios from gigabyte F43 (1.09V/900Mhz), FY1 (1.25V?/1000Mhz), FX1(1.25V?/1000Mhz) have locked voltages for the Rev 2.0 boards. However, if you use robnitro's hacked FY1 bios, this will allow you to change the voltage using cgminer or Trixx. ;) I tested this bios and the voltage control works well, however I still run at 1.09 as going below makes the cards unstable @1100Mhz.
3. The FT0 bios was also hacked by robnitro and according to users, the voltage control works as well.

Regardless of the voltage unlock capabilities however, the undervoltage/overclocking capability of each specific GPU is closely tied to the ASIC quality. If you have a card with a very low ASIC quality, chances are you'll have to bump the voltage or even underclock it; depending on what you are aiming for, YMMV.

What PSU?  6x 7970s on 1300 watts?  What voltage do you run?  That's really good

My 6x7970s with mobo,cpu,ram,etc pull 1650 from the wall.  But I also have a bunch of fans hooked up, so it's probably more like 1550.  That's at 1.1 vddc.  There are 2 PSUs though, one is a 1200 Gold the other is a just a 520 watt 80+.  I'm guessing the little psu isn't helping.

**ahh I also have a 3770k on there though, forgot about that.  will be dropping in a g1610 this weekend.  Got a few of 'em sitting in my closet, just waiting for me to build dedicated racks  :D

here you go bro if you guys want to jump on some while they are only $42.99
http://www.amazon.com/Intel-Celeron-2-60GHz-Processor-BX80637G1610/dp/B00B4BJYVU

They wont even accept lower voltage when you underclock them? I've got a few voltage locked cards that works in a strange way. Trixx lets me set voltage to pretty much whatever I want but the actual voltage will only change in the following steps when certain conditions are met.

stock 950Mhz/1.25V

<850MHz setting voltage to anything lower than 1.150V will set it it to 1.150 (or it was 1.125 cant really remember), if you raise clocks above 850 it defaults back to 1.25V

<700Mhz the same as 850 but this time with 0,95V

The way I figured they were working is that they let you set the voltage stages predefined in the "boost" profile in the bios as long as the frequency requirement was met. They are all xfx cards but I tried some other 7950 boost bios' and nothing changed, I just figured most locked cards behaved in a similar way but if the gigabyte ones really are locked like you say I'll make sure to stay clear of them.


And yes, I have confirmed the power consumption actually goes down.

Thinking of throwing a 5th gigabyte card in but might be cutting it fine .

I have a watt monitor plugged into the wall.

Also with my psu comes with a USB dongle and app to read power usage.

Both are reading different wattages. Which reading should I go with when seeing if my psu is big enough to support the wattage on the new card.

My psu is Corsair AX-1200i 1200W i 80+ Platinum Certified ATX PSU

i have a system that runs 3x7790 cards at 300mhash, it takes 220 watts

I haven't measured them recently since they run on ~250 volt and kill-a-watt runs on ~125v. They are likely at or slightly 100% capacity. Clock speeds vary from 1070-1140 (150 mem) and 1.05v. All cards are reference on a Z77A-g45 + G530 or 890FXA-GD70 + 145.

10x HD7950 @ 3Kw day n night.

you should be fine i pull under 950w from the wall with 4 cards in the same psu

I'm pulling about 930W from the wall according to the Kill-A-Watt EZ with this setup:

Z77A-GD55, Celeron G1610 Ivy Bridge, (5) Sapphire 7950s under-volted to 0.968 and running stock clocks (925/1250) hashing @ 570Kh/s.

That seems really high, you must OC the hell out of them.

Same. I'm surprised you're making any profit at all unless you don't pay electricity.

I have 5 x 7950 in 2 rigs, 2 card rig draws at the wall 714w, 3 card rig draws at the wall around 1080w. So both my rigs draw about 1.8kw and thats fully overclocked. When I did the tests with single card, not overclocked it draw 200w but full overclock increase power draw to over 300w.

Hard to find a household outlet to run this power level.

Are you running windows 8?

Windows 7 for now.  I'm switching to Windows 8 though because apparently that's the only version of windows that will accept (6) 79xx series cards on one motherboard.

no what make the real difference is the voltage, the downclock of the memory, and the psu efficiency

same here 925w on celeron w 4 WF3 7950... that 5th one is probably killing the efficiency it drops like a rock after it goes past 90% or so

Actually just switching my rigs back to BTC from scrypt without changing anything is a 50-150W/rig drop depending on the type/number of cards.