PSU for 4870 CF

[wolf]

i have a cooler master 650W psu with ratings as follows +3.3V@28A,+5V@30A,+12V1@18A,+12V2@18A,-12V@0.8A, +5VSB@2.0A

the system is as per my specs, would this be cutting it close for 2x4870?

 

[TonyStark]

If it has four 6pin PCIe plugs then it was obviously designed to output that power. Otherwise, look for another PSU.

 

[alexp999]

i have a cooler master 650W psu with ratings as follows +3.3V@28A,+5V@30A,+12V1@18A,+12V2@18A,-12V@0.8A, +5VSB@2.0A

the system is as per my specs, would this be cutting it close for 2x4870?

Do you have the rail caps? usually a total power output across the two 12v rail? in A or W? Sometimes on the sticker sometimes in the manual.

 

[wolf]

If it has four 6pin PCIe plugs then it was obviously designed to output that power. Otherwise, look for another PSU.

it has 2 pci-e connectors, but ive run a 9800GTX and a 9600GT at the same time off a antec 550w that had no pci-e power, so im thinking its possible, however these cards together may draw more jiuce than this psu can provide..... i know its SLi certified....

 

[Ketxxx]

I'd say your PSU is fine. Worst case scenario your system will be unstable with 2x 4870s.

 

[Brackish]

I would be careful about running two of the cards.

A decent 750W will give you the overhead for load for two of the cards. The SLI certified sticker with coolermaster psu's can mean two of the low end SLI cards, ie: 8600GT.

From what you stated about the rails you only have 2 +12 @ 18A so only 36Amps for the two cards to run. A psu with 40 or amps would be safer.

Based on my personel experience this like!

 

[alexp999]

I would be careful about running two of the cards.

A decent 750W will give you the overhead for load for two of the cards. The SLI certified sticker with coolermaster psu's can mean two of the low end SLI cards, ie: 8600GT.

From what you stated about the rails you only have 2 +12 @ 18A so only 36Amps for the two cards to run. A psu with 40 or amps would be safer.

Based on my personel experience this like!

Didnt notice that before.

TBH that is really bad for a 650W PSU. to give you some idea, my 650W Corsair can do 52A continous on the 12v rail.

What model of Coolermaster is this. i believe that one of thier ranges is not far off a generic with a coolermaster sticker on it.

 

[boogah]

was gonna tell u to get one of these but they're out of stock now
has 4 6-pin pci-e and an 8-pin

http://forums.techpowerup.com/showthread.php?t=66176

 

[erocker]

My PCPower&Cooling 750Quad runs two just fine! Deffinitely get a quality PSU with four connectors.

 

[AsRock]

My PCPower&Cooling 750Quad runs two just fine! Deffinitely get a quality PSU with four connectors.

Hell yeah sweet ass PSU.

 

[wolf]

http://www.newegg.com/Product/Product.aspx?Item=N82E16817171014

thats her there, and yes shes a cheapie, but like ive said ive run high power cards off a lesser psu before...... if i try it, can it blow up the cards with it? or will just the psu go?

otherwise its looking like a corsair TX750

 

[Pinchy]

Id say it *should* be fine, but you MAY experience instability. It shouldnt be something that will just blow up straight away though.

 

[AsRock]

http://www.newegg.com/Product/Product.aspx?Item=N82E16817171014

thats her there, and yes shes a cheapie, but like ive said ive run high power cards off a lesser psu before...... if i try it, can it blow up the cards with it? or will just the psu go?

otherwise its looking like a corsair TX750

How hot does it get in this room you have your computer in ?.. I ask due to if it's high the PSU will get real hot witch will result in performance loss + it's only 70 efficiency so that means even more heat and to be honest i would not put a 120mm sleeve fan in a PSU which sounds like it'l get hot.


This one is much better.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139005

I use this one and seen the temps around 50c @ 390w in a room temp of 31c.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817341011

The temp is kinda on the high side but it's frigging hot in the house as is and if you have these hot summers i think that one you picked will either pop or some thing or like my other did shutdown the system when it hit 350w load rated 600w.

EDIT: the one you picked only has 2 6pin connectors so some thing like the PC Power for sure as the HX does not have 4x6 pin connectors.

 

[wolf]

the psu never gets hot, the system runs very very cool, as is the room it is in.

i got a zalman ZM-MFC2 today, and from what ive heard its quite accurate. it puts the entire system consumption at 420w at FULL 3dload, with the CPU oc'ed and all the hard drives etc.

would that leave enough spare for the next 4870?

 

[alexp999]

That is the coolermaster I was thinking of. I looked at it at the time thinking how good the price was but it is just a branded generic really. You can try it, and I would imagine worse case is the PSU could blow which might take a lot of stuff with it, but I would expect it to just BSOD or lockup under GPU load.

Your call.

 

[wolf]

it is just a branded generic really.

i've used generics before and this thing is in a different league from those.

my only real concern is if it has enough power to do the job, not the quality of the parts inside it.

i will eventually replace it, but im weighing up the risk of wether it will even temporarily power two 4870's...

 

[alexp999]

i've used generics before and this thing is in a different league from those.

my only real concern is if it has enough power to do the job, not the quality of the parts inside it.

i will eventually replace it, but im weighing up the risk of wether it will even temporarily power two 4870's...

It might, and I think it will boot. But that just seems incredibly low for the 12v rails on a 650W, like you get on generics. And I dont think there will be enough A.

I am 99% sure it will probably just crap out and BSOD or lockup during 3d mark or something. But theres always that small 1% chance it could go pop.

You could probably help it along by unpluggin anything unessecary. Without compromising the rest of your system.

 

[wolf]

yeah 2 rails with 18 amps each doesn't seem like a huge amount for 2 decent power cards....

 

[alexp999]

yeah 2 rails with 18 amps each doesn't seem like a huge amount for 2 decent power cards....

The graphics cards will probably need 18A each on thier own! lol, I think under full load the 4870 pulls about 160W. 160W / 12V = 13A

Thats for each card. And usually in multirail systems there is a cap across the two rails. E.g Each is rated for 18A but the combined output is only say 30A.

 

[wolf]

not to mention i will have them both overclocked in the vicinity of 850/4400mhz.... looks like ima go for a corsair TX750 when i get my second 4870.

from memory 12v can draw 730 of those watts and can hold 60 amps continuous.

 

[wolf]

i did it!

so yeah i did it,

went with a Zalman ZM850-HP, 6x12v rails, 2 with 22 amps continues 24 peak, and the other 4 rails with 18 amps continuous and 22 peak, with 768watts continuous able to be fed to them.

the second 4870 is a gigabye and both run at 825/4000 in crossfire with alternate fan controll for low temps. my system now is INSANE, a cut above the rest.