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Is my 550w PSU okay to CF 6850's?

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May 21, 2012 3:06:51 AM

Well I have the OCZ-ZS550 PSU, which has a +12v of 456w. Would that be enough to power two 6850's plus a AMD X6 1035T?

Also would it be okay to OC the CPU and GPU's during crossfire configuration?

More about : 550w psu 6850

a b ) Power supply
May 21, 2012 3:11:30 AM

itll take approx 430w to power both cards alone, but this heavily relies on the quality of the psu.
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a b ) Power supply
May 21, 2012 3:17:32 AM

Quote:
Absolutely NO. get a 750w Psu or mininum 650w psu.
my suggestions-
antec high current gamer 750w
corsair GS700
xfx pro series 650w
corsair 650 TX V2


a simple google search will disagree with what your saying, and more agree with what i'm saying.
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May 21, 2012 3:28:17 AM

dudewitbow said:
a simple google search will disagree with what your saying, and more agree with what i'm saying.


Not really. I mean, I just did one and most people recommend 650W as the bare, bare minimum. I wouldn't do 550W on it. Generally if the PSU only has 2 PCI-express connectors, it's only designed for a single card.
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a b ) Power supply
May 21, 2012 3:31:49 AM

frozenlead said:
Not really. I mean, I just did one and most people recommend 650W as the bare, bare minimum. I wouldn't do 550W on it. Generally if the PSU only has 2 PCI-express connectors, it's only designed for a single card.

Of course i would recommend a 650w psu, but saying absolutely not isnt the way to go. it is possible with a quality psu, i just wouldnt recommend it.
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May 21, 2012 4:00:14 AM

Appreciate the responses. My searching came up with mixed results. Max consumption for two 6850's seem to be from 250w-460w.
Including my ~100w CPU plus other peripherals would put me about at the limit.
I might take my chances crossfiring, if I end up buying a couple more games this year.
Although it seems too risky for now.
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Best solution

a c 266 ) Power supply
May 21, 2012 4:41:20 AM

Your power supply will be fine. People telling you that 750 watts is necessary for 2 x HD6850s have no concept of how little power most computers need.

From Guru3d.

" Our test system is based on a power hungry Core i7 965 / X58 based. This setup is overclocked to 3.75 GHz. Next to that we have energy saving functions disabled for this motherboard and processor (to ensure consistent benchmark results). On average we are using roughly 50 to 100 Watts more than a standard PC due to higher CPU clock settings, cooling, additional cold cathode lights etc.

With that in mind. Our normal system power consumption is higher than your average system.

Graphics card IDLE WATT FULL WATT
Radeon HD 6850 1024MB 176 278
Radeon HD 6870 1024MB 173 295
Radeon HD 6850 CrossfireX 186 393
Radeon HD 6870 CrossfireX 184 421


http://www.guru3d.com/article/radeon-hd-6850-6870-cross...


Now if you are overclocking everything in your computer to it's max you might want to go with 600-650 watts.


AMD recommends 550 watts for HD6850 Crossfire. That assumes a junk power supply. The OCZ ZS is a very good power supply.


http://www.realhardtechx.com/index_archivos/Page362.htm


So basically if you overclock everything to it's max and run Prime 95 and Furmark 24/7 you might need a more powerful power supply. At normal settings with normal useage you are fine.




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a b ) Power supply
May 21, 2012 4:52:27 AM

muffed said:
Appreciate the responses. My searching came up with mixed results. Max consumption for two 6850's seem to be from 250w-460w.
Including my ~100w CPU plus other peripherals would put me about at the limit.
I might take my chances crossfiring, if I end up buying a couple more games this year.
Although it seems too risky for now.

total SYSTEM power is 390 watts
http://www.tweaktown.com/reviews/3602/his_radeon_hd_685... <-- proof
http://www.guru3d.com/article/radeon-hd-6850-6870-cross... <-- proof
the approximate draw of the card is 129 watts (22 amps rounded up)
http://www.techpowerup.com/reviews/HIS/Radeon_HD_6850/2... <-- proof

your PSU with TWO 6 pin PCI connectors (one for each card) and will provide 20.4 (of 38) AMPS @ 84.6% efficiency (i highly doubt it will down down much with 1.4 more amps!)
http://www.jonnyguru.com/modules.php?name=NDReviews&op=... <-- proof

so the bottom line is your good. the max load is 73% of your PSU, which it will handle; read the last link.
your 12 volt rail has the two power connectors and will provide enough power to run the cards.

that is a perfect example of being able to have a quality PSU and run things that normal ones cannot.

EDIT anort3 you find proof faster than me :lol: 
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May 21, 2012 5:20:55 AM

Anonymous said:
total SYSTEM power is 390 watts
http://www.tweaktown.com/reviews/3602/his_radeon_hd_685... <-- proof
http://www.guru3d.com/article/radeon-hd-6850-6870-cross... <-- proof
the approximate draw of the card is 129 watts (22 amps rounded up)
http://www.techpowerup.com/reviews/HIS/Radeon_HD_6850/2... <-- proof

your PSU with TWO 6 pin PCI connectors (one for each card) and will provide 20.4 (of 38) AMPS @ 84.6% efficiency (i highly doubt it will down down much with 1.4 more amps!)
http://www.jonnyguru.com/modules.php?name=NDReviews&op=... <-- proof

so the bottom line is your good. the max load is 73% of your PSU, which it will handle; read the last link.
your 12 volt rail has the two power connectors and will provide enough power to run the cards.

that is a perfect example of being able to have a quality PSU and run things that normal ones cannot.

EDIT anort3 you find proof faster than me :lol: 

Thanks! very useless links. I think i'll go ahead and get that second 6850 instead of selling my current one for a 7850.
I don't know if it matters but, i also have 5 case+cpu fans, and 4 hard drives in my system.
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a c 266 ) Power supply
May 21, 2012 5:27:16 AM

You mean useful links?

Case fans use 3-5 watts each and hard drives use less than 10 watts each. You are still well within the safe range.
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May 21, 2012 6:20:31 AM

Lol oops. *USEFUL

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May 21, 2012 6:20:45 AM

Best answer selected by muffed.
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a b ) Power supply
May 21, 2012 12:37:01 PM

This topic has been closed by Mousemonkey
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