Each PCIe slot can pull 75W however AMD has designed their cards to reduce the draw on the PCIe bus (in favor of PCIe connectors).  This is because the connectors are more reliable source of power.

8pin = 150W
6pin = 75W
bus = 75W

I have never had a 5970 pull >300W.   The 294W is AMD TDP spec (as in the max heat the card can handle without a dangerous failure).  That doesn't mean the card draws 294W.  At 100% load I measured (using kill-a-watt) 248W draw.


What is your power draw @ the wall?  I guarantee you it is no where near 1200W.  Probably somewhere around 900W - 1000W.

I am using this power supply.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817153148

Maybe I was wrong about 850W.  I am going off memory.  Once I got the system solid I removed the kill-a-watt to use on my desktop (which I am also fiddling with).   I will recheck the wattage tomorrow but I am sure it isn't 1200W+.

Bringing your mem clock down to 300 will reduce heat & power output significantly.   The difference between mem @ 500 and mem @ 300 is probably 20W a card.  When I setup this rig I couldn't go below 300 but I haven't check recently and I saw a thread where someone was running 5970s @ 200 Mhz memory.  I may need to revist my settings.  

If you can't push the system further heat is likely your problem not power draw.  The only way to know for sure is measure it all the wall with a meter like "kill-a-watt".    In computer bios turn off everything you aren't using.  Onboard sound, EIDE controller, etc.  They may not be much but each pulls some power and likely is doing nothing.  If your motherboard has onboard video make sure that is disabled too.  Your CPU should be lowest power model you can find.  For AMD Sempron runs @ 45W max and idles at half that.  You can underclock/undervolt it (depends on MB BIOS options) and cut another 10W right there. Using linux distro and usb drive saves some power too.  Windows loves to use swap file for no reason and HDD is going to pull 5W or so.  It may seem like nickles and dimes but all those watts add up.

If you do nothing else work on getting mem frequency down.  Running @ 500MHz is just burning up cash and limiting your overclock potential.

If the voltage regulator gets too hot it will lock up the system.  Usually when GPU core is too high it results in artifacts, and bad results but if Voltage regulator overheats it is hard lock without warning.

he is totally over clocking the cards to at least get 833 mh/s per card. And that is one reason i sorta doubt his power
usage as the cards would be getting pretty darn close to 275 watts each. 296 is the TDB (whatever the acronym is).
Also the mining hardware chart also shows some serious wattage per card as they get overclocked/over voltage if necessary.
Then add the MB/ram/proc/fans/HD or flash drive/and PSU inefficiency... seems to me you would easily be over 900 watts and expect to have
a 1000-1200 watt psu.

but these are rough calcs and based on other people posting their power usage with multiple 5970s.

Apologies for bumping an old thread (well, sorta old anyway) but I've been running my two 5870s + single 5970 for a couple weeks now without any problem.  Power at the wall reads right at 850W +/- a few Watts but I have that issue where my CPU is pegged at 100% usage when I'm mining, so I'm guessing that's drawing a few watts.

So anyway at lunch today I went and bought a new Corsair AX1200.  It's so square and round and fuzzy and I can pets him  I'm probably going to return the AX850 and run my rig on the 1200 instead.   So now my question is:  Can I run my two 5870s + 5970 + a 6990 off one AX1200?  I can't seem to find a buyer for my 6990 (https://bitcointalk.org/index.php?topic=43682.0) so I'm leaning toward just ripping it open and installing it into my system.

Everything in life has risk.  Obviously for you the risk is not worth the potential reward.

I was just pointing out it isn't as bad as you make it seem.  

I bought 3 more 5970s a couple weeks back for 3 reasons
1) they have good resale value.  check ebay completed sales on used 5970s.  going for $400+.  I expect they will be $300+ even after 7000 series.
So capital loss is reduced.  If one pulled the plug in next two - three months they would be looking at $100 loss per unit.  If they pulled the plug in a year it might be $200 to $300.  Much easier to reach break even if the equipment has value.

2) I have all the parts to build a rig other than GPUs so cost is limited to $1500.  The capital at risk is hedged by good resale value of 5970s.  Last 5 used 5970 auctions on ebay ranged from $450 to $530. The 5970s hold value because they are faster than ANY 6xxx series card except the 6990 (which runs $730).  Even @ $500 a gamer is getting 90% of the performance for 70% of the price.

3) My electrical rates are low ($0.095/kWh) and will go lower pretty soon when utility switches to fall/winter pricing.  That combined with fact I can leave rig in garage (no need to take up space & noise in house) makes it an easy call.

My current 3x 5970 rig uses ~850W at the wall and gets 2.5GH/s.  At current price and difficulty that works out to ~$200 per month net.  Simplisticly that is a break even of ~7 months but that is a crude way of looking at it.  The cards retain value and are slowly depreciating.  I hit break even in two month because the resale value of cards + revenue > capital cost of cards.

i.e.
month 0: $1500 in assets -$1500 cash (spent to buy cards)
month 1: $1200 in assets -$1300 cash ($200 BTC revenue, cards worth ~$400 ea)
month 2: $1200 in assets -$1100 cash (another $200 BTC revenue, cards worth roughly the same, won't depreciate them again until 6 months)
...
month 6: $900 in assets -$300 cash (this is rather conservative.  if 7990 is released or price drops on 6990 then I am devaluing the cards to ~$300 ea)
etc.

Of course that assume revenue stays constant (which it won't over the long run).

To each his own.  For someone w/ high electrical rates or needing to build entire machine it likely isn't worth it.  Someone who can't afford to run more than one (to reduce system cost / GPU) it may not be worth it.  Thats great.  Hopefully people turn off high cost rigs and difficulty goes even lower.

Drivers:
Win7 64-bit
ATI 11.5/SDK 2.4

OCing Software:
Trixx for Core/Memory clocking
MSI Afterburner for fan control

910/300MHz/1.100v both cores

Mining Software:
Phoenix 1.50 with Phatk 2.2

VECTORS2 WORKSIZE=256 FASTLOOP=FALSE AGGRESSION=11 -k phatk

Remote Access Software:
N/A

Results:
411 MH/s per core


You get that with 1 card 1 motherboard?

Here's a little secret:  I buy used Alienware/Dell 875-1100 on eBay for cheap ($75-150)

Everyone wants a 1200w Silverstone or Corsair but frankly those Dell units are rock solid and if anything are watt underrated.  Dell does that to keep its butt covered.  I have 2 5970s and an AMD A8-3850 APU on a single 875 and it's been running for months.  The wiring harness is ugly as hell but who cares?

An Alienware 1100w will easily run 3 possibly 4 slightly undervolted (1000mV).  The thing is ginormous.

If I save you some money:  15LCk9RUgNR3E9pmmEHVkA4TVrGPNvLRVP

 

"Any mobo" is not really a great suggestion. Remember that a 5970 is more or less just 2x 5870s slapped on a single PCB. That means 4x 5970s is the equivalent of 8 5870s, except that they're drawing power through only 4 PCI-E slots. This is a LOT of juice to run through a single mobo (will probably exceed the 75W per slot alotted to PCIE standard and already is 300Watts), and can potentially melt/burn/blow a mobo not designed for high current.

I know it may sound like a waste of money but I'd recommend 2 lower end mobos, or else save up for a super high end mobo.

For PSU, your options are very limited, Silverstone Strider 1500 and ThermalTake ToughPower 1500 are the only two 1500W PSUs I know off the top of my head that are any good, and I'm not totally sure that they'd cut the mustard (probably, but it'd be close). Another reason to potentially break it into 2 comps, instead of dropping $350 on one PSU that might or might not do the job, 2 $150 Gold Rated PSUs will be cheaper, do the job better and save you on your electric bill.

Not to be rude, but I have found mobo with 3 slot in the trashes and use them for mining.

how much did you get your 5970 for ?

PS: next time, post such to "Hardware" sub topic

Ok the 5970 seems to work fine.  At stock clock 725MHz (300 memory) it's doing 320 MH/s.  Time to turn up heat and see what this thing will do (ha famous last words!)

keep in mind that wattage is all on the 12v rail (180*8/12) you need a 120amp (1440w) 12 volt rail you're going to need multiple psu's or to find a 1500w+ power supply somewhere

I'd say ~180w per gpu to be safe , you have 8