Trifire power needs

Crezzlin

Crezzlin

Crezzlin

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I’ve been trying to use quad 6990/6950/6950 with my old Antec Quattro 1000w PSU its about 3 / 4 years old now, but it only has 2x 8pin and 2x6pin plugs so for the 3rd card I have used 2 Molex to pcie adaptors, does anyone know if they will provide ample watts to the card.. The pc will run but I do get the random restart and poor performance under full load with eyefinity so I can only put this down to the lack of power?? Thanks
 
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I wouldn't try and run 1 graphics card entirely from molex adapters.

You may get better power stability with the following:

  • 2 PCI-E power cables directly from the PSU to the HD 6990

  • 1 PCI-E power cable directly from the PSU and 1 made from a molex adapter to each of the HD 6950's
 
Hi thanks, i did try this but still no good.. im sure its a psu prob with the molex.. i used a 6970 on it with the 6990 as the 6970 has 1 8pin socket i had to use a molex adapter and the PC was rebooting under full load still.. :s
 
1000W is really pushing it for quadfire, its probably what i;d recommend for tri fire. i would say 1200W as an absolute minimum for what you plan on doing
 
on a similar note will 850w(cm real power m850) be enough for 6950/70 trifire? same problem in terms of the lack of connectors.

reading a previous thread people said they where getting 900w at the socket, tho I remember stulid or someone else saying 850w will be enough.

if not whats the suggest psu with 6 pci-e connectors(not jus cables)?

btw I have 2x 6950 toxic(each has 1x6pin and 1x8pin) not 'normal' 6950(2x6pin), may get 3rd card in near future once prices drop.
 
to answer this once and for all:
if you havent unlocked the cards and turned them into 6970's then this is the power you will need from the PSU (leaving a reasonable overhead for overclocking and stuff):
1x 6950: ~450W
2x 6950: ~650W
3x 6950: ~900W
4x 6950: ~1150W
http://www.anandtech.com/bench/Product/293?vs=299

1x 6970: 500W
2x 6970: 750W
3x 6970: 1050W
4x 6970: 1350W
http://www.anandtech.com/bench/Product/292?vs=298

to work everything out i was using the difference between the cards in single and crossfire to get the amount of power adding another card will require, then adding 50W to that to allow for overclocking. then i made sure there was at least 100W to spare.
you might be able to get away with slightly lower than these estimates, but i would rather recommend something too high than too low
 
Erm Crezzlin, that's quadfire you're tying to run there. The 6990 is two 6970s underclocked (but a BIOS switch can turn them back to full speeds) slapped into one card. The best method is to buy a new PSU, have a look at Reaper's post in post #6 to see how much wattage you'll need.

But if I was you I would sell one of the 6950s. Quadfire has really poor scaling and in some cases doesn't bring any improvement over trifire. What resolution do you play on?
 
both my toxics unlock and @stock(for toxic) which is core same as 6970 but slightly lower memory.

hmm so corsair hx1050 but does it have 6x psu connectors?

is the seasonic p1000(new seasonic platinum) worth £224(elsewhere)?

guess I'll have to change psu if/when I add a 3rd card, hope I have a job by then(the £70+ I'm having to put towards getting the extreme7 fixed could have gone towards the new psu).
 
I play on 6000x1200 with bezel correction, only reason i would like quad is bf3 runs at 60fps steady or may dip to 50 in some games,, i had a game called Hard Reset that would run ok on 3 cards but a little bit of lag anyway that game would run on max settings with quad fire so i was wishing BF3 would just have the edge with 4 GPU'S.. runs smooth with 3 but on medium effects etc.. :)
 
fowler002 said:
both my toxics unlock and @stock(for toxic) which is core same as 6970 but slightly lower memory.

hmm so corsair hx1050 but does it have 6x psu connectors?

is the seasonic p1000(new seasonic platinum) worth £224(elsewhere)?

guess I'll have to change psu if/when I add a 3rd card, hope I have a job by then(the £70+ I'm having to put towards getting the extreme7 fixed could have gone towards the new psu).
Click to expand...


Why are you getting the Extreme7 fixed? I have my board up for sale in the 2nd hand section.. :)
 
Crezzlin said:
Why are you getting the Extreme7 fixed? I have my board up for sale in the 2nd hand section.. :)
Click to expand...

well 'fixed' in that sending to asrock for a replacemnt, I've already spent £35 rma'ing to ocuk who rejected it with 'warranty void, bent pins' routine(£22 for the testing/return cost + £13 to post to them in the first place). I've not contacted them yet but going by what ge3000 has said(plus he's sent me a copy of the email reply they sent him) asrock ask for 25euros/£15 to cover the return cost + it'll cost me another £15+ to post it out to holland in the first place.

I'm thinking about taking a needle thin screwdriver to the couple of bent pins to see if I can save myself the £30-£40, other option is to put it on the mm as faulty and see if I can get back like £150 of the £245(£210 + £35) its cost me thus far.
 
Reaper 392 said:
to answer this once and for all:
if you havent unlocked the cards and turned them into 6970's then this is the power you will need from the PSU (leaving a reasonable overhead for overclocking and stuff):
1x 6950: ~450W
2x 6950: ~650W
3x 6950: ~900W
4x 6950: ~1150W

1x 6970: 500W
2x 6970: 750W
3x 6970: 1050W
4x 6970: 1350W
Click to expand...

Real world test:

i7-2600K @ 4.6GHz
TriFire unlocked HD 6950 Sapphire TOXIC's @ 980MHz/5400MHz

Prime95 running 8 threads, CPU @ 100% load
Furmark running all 3 GPU's @ 95%+ load

Maximum power draw from the mains 850W.

1250W Gold rated PSU, say 92% efficient.

Actual output from the PSU ~782W.

So Reaper 392's figure for 3xHD 6970's is pretty close to the mark as the size of PSU needed as you don't want to be running a PSU too close to it's maximum output for long periods.
 
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but 'realworld' useage wouldn't have prime + furmark running at the sametime, also I'm not going to be overclocking all 3 to 980mhz on the core leaving @ 880mhz maybe oc to 900mhz and have a i2500k not i2600k.

but think the 850w psu wouldn't be ideal :)
 
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fowler002 said:
but 'realworld' useage wouldn't have prime + furmark running at the sametime, also I'm not going to be overclocking all 3 to 980mhz on the core leaving @ 880mhz maybe oc to 900mhz and have a i2500k not i2600k.

but think the 850w psu wouldn't be ideal :)
Click to expand...

Maximum power usage then.

Just running Furmark, so very little CPU load, with the GPU's @ 880MHz/5200MHz gives a power draw of 630W at the mains.

So ~580W from the PSU.
 
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