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HD5770 crossfire with my PSU opinions please

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a b U Graphics card
November 30, 2010 9:06:57 AM

Hello you can see my system in my signature, my question you people is; How likley is it that I will be able to safely crossfire two vapour X HD5770's with my PSU

Here is a link to the specs of it.

http://www.ocztechnology.com/products/power_management/...

The thing is If i have to buy a new PSU I can not afford the new graphics card so....

Thanks for your advice and opinions

Adam
a b U Graphics card
November 30, 2010 9:50:43 AM

I wouldn't advise CF'ing with that wattage. You're going to need minimum 650W for a CF setup in your rig i'm sorry to say.
November 30, 2010 11:29:04 AM

I'd also not recommend it. It could be possible if you downclocked and undervolted both cards and the CPU, but other than that they'd draw too much power.
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a b U Graphics card
November 30, 2010 3:17:08 PM

I have used online PSU calculators and they all say that minimum psu should be 391watts and recomended is 441watts, does that change your opinions?
a b U Graphics card
November 30, 2010 4:14:54 PM

With crossfired 5770's a minimum of 600W PSU is recommended by ATI.
a b U Graphics card
November 30, 2010 5:00:56 PM

Do not do it. You make it sound like you are low on cash. I do not think you would like to lose 2 GPUs and a PSU. :( 
a b U Graphics card
November 30, 2010 10:02:08 PM

jockey said:
With crossfired 5770's a minimum of 600W PSU is recommended by ATI.

Yeah, they reccomend 600 watts for a pair of 5870's as well.
Guess they've overblown the reccomendation so much it doesn't matter that the 5870 uses almost twice the power of a 5770.
a b U Graphics card
December 1, 2010 11:34:21 AM

yeh that's a good point =/ hmm still unsure about what to do =/
December 1, 2010 11:43:43 AM

I believe it is still possible to do so and I don't think it'll make your computer explode, but I'd only do it if you are REALLY short on cash / desperate.
a b U Graphics card
December 1, 2010 1:04:11 PM

I'd say you'll be fine! Look at the spec sheet and you've got a combined 12v+3.3v+5v Amperage of 40A on that PSU, which is a fairly decent brand. 3.3v and 5v are basically legacy outputs as most of the load is on the 12v (so you can asssume as you're not loading the 3.3/5v up you can pull near to the whole 18A off each 12v rail). Max draw for a 5770 is 9A, in reality it never pulls that much, 18A for the Gfx (absolute max) leaves you up to 18A on the 12v rails for the rest of your setup.
I've got a single 5770 on an Antec EA380w with a 3.2Ghz Q9400, 2x case fans, 1xDVD and 2xHDD and that runs no probs. As long as you only have a modest amount of other equipment running off your 12v (HDDs, fans, DVD etc) you'll be grand.
a b U Graphics card
December 1, 2010 2:01:44 PM

MMclachlan said:
I'd say you'll be fine! Look at the spec sheet and you've got a combined 12v+3.3v+5v Amperage of 40A on that PSU, which is a fairly decent brand. 3.3v and 5v are basically legacy outputs as most of the load is on the 12v (so you can asssume as you're not loading the 3.3/5v up you can pull near to the whole 18A off each 12v rail). Max draw for a 5770 is 9A, in reality it never pulls that much, 18A for the Gfx (absolute max) leaves you up to 18A on the 12v rails for the rest of your setup.
I've got a single 5770 on an Antec EA380w with a 3.2Ghz Q9400, 2x case fans, 1xDVD and 2xHDD and that runs no probs. As long as you only have a modest amount of other equipment running off your 12v (HDDs, fans, DVD etc) you'll be grand.


Thanks for the reply, I have three SATA hard drives but one is green, 1 opitical driver, I have a wirless network card and an antec 900 case (so the big fan on top, and three smaller fans)

Would that count as a modest amount? =) thanks again
a b U Graphics card
December 1, 2010 2:02:08 PM

MMclachlan said:
I'd say you'll be fine! Look at the spec sheet and you've got a combined 12v+3.3v+5v Amperage of 40A on that PSU, which is a fairly decent brand. 3.3v and 5v are basically legacy outputs as most of the load is on the 12v (so you can asssume as you're not loading the 3.3/5v up you can pull near to the whole 18A off each 12v rail). Max draw for a 5770 is 9A, in reality it never pulls that much, 18A for the Gfx (absolute max) leaves you up to 18A on the 12v rails for the rest of your setup.
I've got a single 5770 on an Antec EA380w with a 3.2Ghz Q9400, 2x case fans, 1xDVD and 2xHDD and that runs no probs. As long as you only have a modest amount of other equipment running off your 12v (HDDs, fans, DVD etc) you'll be grand.


Thanks for the reply, I have three SATA hard drives but one is green, 1 opitical driver, I have a wirless network card and an antec 900 case (so the big fan on top, and three smaller fans)

Would that count as a modest amount? =) thanks again
!