I think one should be fine - heavily OCd it should be shy of 200W. Two 5830s will definitely draw more than a single 6970 though, I wouldn't push it 
thanks...I should be setting that up tomorrow or sunday
Topic: How many 6970's per 1500W PS (Read 2195 times)
I should be setting that up tomorrow or sunday
I think one should be fine - heavily OCd it should be shy of 200W. Two 5830s will definitely draw more than a single 6970 though, I wouldn't push it
i think everybody is right about adding another 6970 beeing not a good idea.
however now i'm wondering if i can move one of my 5830 cards onto it instead.
that it might have enough power for.
perhaps even 2 of them?
however now i'm wondering if i can move one of my 5830 cards onto it instead.
that it might have enough power for.
perhaps even 2 of them?
Totally suprised by the power draw of these things.. 425mh/s for what seems to be 275W+.. the +20% must be increasing voltage to hit those marks.
I have them overclocked to 950-960 and ram set at 240
fans running at 100%
one of the reasons i want to watercool them is to get them quiet.
Are you sure everyone is talking about the same thing here?
My MSI Reference 6970s can NOT hit 950mhz stable without overvolting, and their stock clock is like, 880 IIRC. They can't even hit 920mhz at stock voltage. I get a solid 400mh/s at 910mhz.
Also, downclocking the memory below 300mhz
I have 2 XFX CNFC 6970's (crossfired for gaming)@ 935/1375,PCS @ +20 (fan @ 85%,temp 70-73c with 3 80mm helper fans)& get 425 mhs from each.When OC'ed like that my whole rig uses 720 watts(using Kingwin 800 watt).I'm not OC'in anymore till I upgrade my PSU to 1000 watt or more.
No luck for me either with downclocking mem so I left it @ stock
I would think 1500 watts would be cutting it too close for 5 of these,escpecially if OC'ed.
You can probably just barely fit 5 6970's comfortably with a 1500W PS if you flash the BIOS on all the cards so that the mem is at something low, like 150-300MHz, and don't overvolt the cards at all. Lowering the mem clock significantly reduces power consumption (and heat levels for GPU!) for me without hindering performance in the slightest, so I recommend it.
Mine is running at 400mhash/s with a temperature of 80 degree celsius, I fix the fan at 85%, seems to be running well all along.
what are your clock rates/power settings/voltage? as well as ambient temperature? 
Mine is running at 400mhash/s with a temperature of 80 degree celsius, I fix the fan at 85%, seems to be running well all along.
I have them overclocked to 950-960 and ram set at 240
fans running at 100%
one of the reasons i want to watercool them is to get them quiet.
Are you sure everyone is talking about the same thing here?
My MSI Reference 6970s can NOT hit 950mhz stable without overvolting, and their stock clock is like, 880 IIRC. They can't even hit 920mhz at stock voltage. I get a solid 400mh/s at 910mhz.
Also, downclocking the memory below 300mhz
I'm using Clocktweak to set my Core to 960, Mem to 250 and Power to +20
i guess setting power to +20 is over volting... but i'm not manualy setting the voltage.
I get steady 429-430 Mh/s
Weird indeed. Mad, if you have a voltmeter handy I would check that you're not getting bad voltage sag on any of your rails. Also if your kill-a-watt lookalike shows volt readings on your mains, make sure that hasn't dipped significantly. Anything < 110VAC is bad news for your PSU.
It really sounds like you've got some phantom draw or ineffeciency somewhere.. a whole 6970 could fit in the difference between our rigs.
It really sounds like you've got some phantom draw or ineffeciency somewhere.. a whole 6970 could fit in the difference between our rigs.
from what i understand setting fans to 100% pulls a lot of power... read somewhere 20W? not sure.
also from my comments above setting Power to +20 may be pulling more power then expected. not sure there either.
as for line power... my UPS (in adjacent room) sais i'm getting 121v
I do have a volt meter and i will check voltages later. i suppose connecting it to any molex connector will tell me what the volts are.
Weird indeed. Mad, if you have a voltmeter handy I would check that you're not getting bad voltage sag on any of your rails. Also if your kill-a-watt lookalike shows volt readings on your mains, make sure that hasn't dipped significantly. Anything < 110VAC is bad news for your PSU.
It really sounds like you've got some phantom draw or ineffeciency somewhere.. a whole 6970 could fit in the difference between our rigs.
It really sounds like you've got some phantom draw or ineffeciency somewhere.. a whole 6970 could fit in the difference between our rigs.
I have them overclocked to 950-960 and ram set at 240
fans running at 100%
one of the reasons i want to watercool them is to get them quiet.
Are you sure everyone is talking about the same thing here?
My MSI Reference 6970s can NOT hit 950mhz stable without overvolting, and their stock clock is like, 880 IIRC. They can't even hit 920mhz at stock voltage. I get a solid 400mh/s at 910mhz.
Also, downclocking the memory below 300mhz
PowerSupply is a silverstone strider 1500W 80 plus silver.
all GPUs have memory clocked down to 250 mhz
affinity is set to first core, done in batch file
all GPUs have memory clocked down to 250 mhz
affinity is set to first core, done in batch file
Well that is just WEIRD! Widely divergent power draws with roughly the same settings and equipment.
ya i'm pulling between 1100 to 1200w
That seems like a lot for 4 6970s.. I've got a rig with 4 6950s that only pulls about 800W, and they're basically the same chipset. The 6970 has a slightly higher stock voltage (1.175V), but it doesn't seem like enough to account for a 300W difference..
Three potential sources of higher load.
Power supply. One that is 75% efficient vs 90% efficient will add 100W to 150W additional AC on the same 800W DC load.
Memory Clock. At full clock these memory on these cards suck down some juice. In my experience downclocking from 1375MHz to 300MHz saves 30W a card.
On a quad core if you have the 100% CPU bug you will be burning 10W-30W extra. Setting affinity to a single core can reduce that 70%.
PowerSupply is a silverstone strider 1500W 80 plus silver.
all GPUs have memory clocked down to 250 mhz
affinity is set to first core, done in batch file
ya i'm pulling between 1100 to 1200w
That seems like a lot for 4 6970s.. I've got a rig with 4 6950s that only pulls about 800W, and they're basically the same chipset. The 6970 has a slightly higher stock voltage (1.175V), but it doesn't seem like enough to account for a 300W difference..
Three potential sources of higher load.
Power supply. One that is 75% efficient vs 90% efficient will add 100W to 150W additional AC on the same 800W DC load.
Memory Clock. At full clock these memory on these cards suck down some juice. In my experience downclocking from 1375MHz to 300MHz saves 30W a card.
On a quad core if you have the 100% CPU bug you will be burning 10W-30W extra. Setting affinity to a single core can reduce that 70%.
ya i'm pulling between 1100 to 1200w
That seems like a lot for 4 6970s.. I've got a rig with 4 6950s that only pulls about 800W, and they're basically the same chipset. The 6970 has a slightly higher stock voltage (1.175V), but it doesn't seem like enough to account for a 300W difference..
Have you over-volted these cards further? Any other high-power components in the rig?
and other then MB, CPU ram and harddrive.
no extra components.
I have them overclocked to 950-960 and ram set at 240
fans running at 100%
one of the reasons i want to watercool them is to get them quiet.
ya i'm pulling between 1100 to 1200w
That seems like a lot for 4 6970s.. I've got a rig with 4 6950s that only pulls about 800W, and they're basically the same chipset. The 6970 has a slightly higher stock voltage (1.175V), but it doesn't seem like enough to account for a 300W difference..
Have you over-volted these cards further? Any other high-power components in the rig?
I put in 3, as much as I am tempted to add in another, I find it hard to dissipate the heat and also worry that any sudden spike will kill the PSU. Better be safe than sorry.
I have all my video cards in a mining rack.
heat isn't a problem. also this weekend i plan to watercool all my 6970 video cards and dump the heat into my cold air vent... warm the house.
I recommend you get a PSU with a single 12V rail.
I don't realy want to shell out more money for another powersupply.can't justify the extra cost.
what i have works... i just want it to work better, more effeciently.
I recommend you get a PSU with a single 12V rail.
I put in 3, as much as I am tempted to add in another, I find it hard to dissipate the heat and also worry that any sudden spike will kill the PSU. Better be safe than sorry.
I'm a little confused.. if you really meant 5970 you might want to edit the topic and OP
myself i never said i had a 5970... nope don't have anyi have 8 6970's total...
just trying to cram more onto a single motherboard...
saves on power in the long run... i think
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