Whats the recommended PSU watts for 2x 6990 xfire cards

evilgummybear

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Im about to get 3x 6990 cards at a super cheap price that i cannot refuse, its pretty much a bargain.
I have currently using antec 1250w psu quatto.

Will this be enuf to run 3x xfire?
 
You can't run a 6990 in three way, only in 'normal' crossfire on a board that supports quad crossfiring,
buy three if its a deal, then sell one on or keep as a spare in case of disaster :p
and no, that psu wont handle three in any case, 750w psu is recommended for one card alone
Moto
 

evilgummybear

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yeah i have an hafx case. Damn here i thought 1250w psu would be enuf for 3x 6990.
But it seems moto said you cannot do 3way xfire???
im pretty much getting 1x 6990 for 200 bucks per card. such a bargin from a good friend :)
 

dork_police

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Yes you cant run 3x6990, as 4x GPU is the max that we can go, so you can only run 2x6990 (which is basically 2x 2x6970's)...

Wattage wise a 1250 should run them, although you will be cutting it fairly close (depending on the rest of your system)..

if you give more details as to what cpu, motherboard, drives etc then we can give a more precise answer if the 1250Watt PSU will suffice...

regards
 

evilgummybear

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i got amd 955 be (OC to 4ghz)
msi k9a2 cd mb
dd2 4gb ram
1250 antec quattro psu
hafx case
corsair h100
3x sata hdd + dvd drive

i might have to chg mb/cpu to avoid bottleneck, but thats no issue can be sorted out easily. AMD 955 is still a wonderfull CPU once overclocked in my opinion, and dd2 is appearently not much of a speed difference to ddr3 conversion.
 

st4rkill3r

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Heh, do u really need 2? 1 of those is pretty awesome, u planning to run games in 2500x1600 maxed out?!? otherwise it's a total overkill, not to mention your CPU might bottleneck the card.
 


Since he is getting it anyway, the possibity of a bottleneck doesn't matter as it will still run as much as teh CPU can handle no matter what he decides.

But keep in mind, most games are only limited by the GPU, so its not really relevant to say that CPU would bottleneck.
 

dork_police

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Okay I went onto one of those PSU calculator sites, I overclocked the cpu put 2 6990's in 5 drives a couple of fans a dvd and a few other goodies...

at full system load 1210 Watts which is really close to your 1250W ceiling...
That being said, I would say get another PSU that is 1400 Watts or something thereabout... Or just use one of the 6990's and ship the other 2 to my address (I'll test them for you :D)

regards
 

dork_police

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well, can you blame me for trying :D?

anyway hope that i pointed you in the right direction - or helped in any way.




P.S. I will always welcome a 6990 that is stranded on my doorstep :)

enjoy mate
 

beenthere

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You can accurately and objectively determine the PSU requirements in watts and 12v rail amps. for this or a future build from the link below. It's easy and accurate. Give it a try and then you'll be able to help yourself and other PC enthusiasts in the future.

http://www.tomshardware.com/forum/314712-28-please-read-determine-power-required

IT'S BETTER TO TEACH A PERSON HOW TO FISH THAN GIVE THEM A FISH FOR DINNER !