Power requirement for 2 gigabyte gtx 460 oc

[piego59]

Hello,
hi i got a i7 920 , which i haven't yet overclocked but will do soon when i got my new motherboard (asrock extreme )
i will put together 2 gtx 460 oc by gigabyte

can my 700 w power supply handle it? (manufacturer is Kraun)
spec: DC output : +5v-/25A,+3,3v-/22A,+12v1-/16A,+12v2-/16A-12v-/0,3A,+5v SB-/2,5A

 

[COLGeek]

It should be okay. Not familiar with the brand, but it should suffice.

Good luck!

 

[vilenjan]

Hello,
hi i got a i7 920 , which i haven't yet overclocked but will do soon when i got my new motherboard (asrock extreme )
i will put together 2 gtx 460 oc by gigabyte

can my 700 w power supply handle it? (manufacturer is Kraun)
spec: DC output : +5v-/25A,+3,3v-/22A,+12v1-/16A,+12v2-/16A-12v-/0,3A,+5v SB-/2,5A

Your power supply is the definition of trash. You have 2 12v rails that combined output 32A. 32x12=384W.

So you technically have a 450W at best that has been re-branded as a 700W (for no reason at all). I am gonna take a wild guess that its not 80plus certified too.

An OCed 920 i7 is around 160W. A pair of OCed 460s is around 340W. So just right there you are over ur PSU's 12v capability. Add in all the other components, and you need a good 650W PSU with at least 50A on the 12v rail to be safe.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817151088&Tpk=seasonic%20650 Best

http://www.newegg.com/Product/Product.aspx?Item=N82E16817703027 great

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139020 good

http://www.newegg.com/Product/Product.aspx?Item=N82E16817371044&Tpk=antec%20650 ok

http://www.newegg.com/Product/Product.aspx?Item=N82E16817171052&Tpk=cooler%20master%20650 ok


All of the above would be able to run your system, so depending on your budget. The PC power and Cooling unit is probably your best bet as far value/performance right now. The Antec & CM power supplies are as cheap as I would go with your build.

 

[cps1974]

I have 750w psu (cooler master gx 750) for my system with gtx 460 soc SLI, i wouldnt like to take a chance with anything less having checked up my likely power usage (factoring in all other components)

chaz

 

[COLGeek]

The size (wattage) of a PSU is less important than the quality of the PSU, as long as the minimum power requirements are met. That is why I recommend Seasonic PSUs to folks. With PSUs, you get what you pay for.

As for the OP's original question, his current PSU will likely power his intended GPU as long as no OCing is attempted. However, it is definitely a component I would look to replace.

 

[piego59]

thank u all for ur replies

so i think u'r right .... in few words: need new psu

i wasn't planning on this

the computer as it is now is not doing too bad. do u think if i do get a new psu + new video card, the changes will be worth the money...?
by the way the psu doesn't seem to be 80 certified, well spotted

 

[piego59]

The size (wattage) of a PSU is less important than the quality of the PSU, as long as the minimum power requirements are met. That is why I recommend Seasonic PSUs to folks. With PSUs, you get what you pay for.

As for the OP's original question, his current PSU will likely power his intended GPU as long as no OCing is attempted. However, it is definitely a component I would look to replace.

si if understand well, i could sli but not oc or oc but not sli with the currrent psu, is this right?

 

[jmsellars1]

So long as you get a good quality PSU i think 650W would be enough, I'd probably get 700W to be safe.

 

[vilenjan]

The size (wattage) of a PSU is less important than the quality of the PSU, as long as the minimum power requirements are met. That is why I recommend Seasonic PSUs to folks. With PSUs, you get what you pay for.

As for the OP's original question, his current PSU will likely power his intended GPU as long as no OCing is attempted. However, it is definitely a component I would look to replace.

COLGeek, you are incorrect. His PSU is not a real 700W PSU. My previous PSU was a 500W CoolMax PSU (8 years old) and it had combined 33A on it's 12V rails, His 700W psu has 32A. The 12v output required by the CPU + 2 GPUs is more than what his combined 32A can deliver. While some high qaulity PSUs can go over thier maximum stated rating, I don't believe the OP's PSU will. More than likely he will end up with a fried PSU and possible other damaged components.

 

[COLGeek]

COLGeek, you are incorrect. His PSU is not a real 700W PSU. My previous PSU was a 500W CoolMax PSU (8 years old) and it had combined 33A on it's 12V rails, His 700W psu has 32A. The 12v output required by the CPU + 2 GPUs is more than what his combined 32A can deliver. While some high qaulity PSUs can go over thier maximum stated rating, I don't believe the OP's PSU will. More than likely he will end up with a fried PSU and possible other damaged components.

Using a single GPU and no OCing with the OP's PSU should be fine. Anything more than that, then I agree with your assessment.

 

[vilenjan]

si if understand well, i could sli but not oc or oc but not sli with the currrent psu, is this right?

Not really and here is why. a Stock i7 920 is 130W. Stock 460 GTX is 160W. 130+160+160=450. 450/12=37.5. This means you need at least 38A just to power the cpu/gpu combo, and the are few other devices (case fans) that run of the 12v rail, so in reality you need at least 40A. You PSU has 32A. And its never a good idea to load any rail to 100% for prolonged usage, 80% is as high as I would go for the long term. This means you want at least 48A, which most quality 650W PSU and some 620W PSu will have (but not all, you need to read the specs).

Now if you dont OC and dont SLI, you can get by on your PSU. You will load the rails to 90%, which given unknown quality of your PSU, maybe a gamble. Also all the PSU's I listed are at least 80plus certified, and most are bronze or silver certified. This means less energy waste.

 

[piego59]

Using a single GPU and no OCing with the OP's PSU should be fine. Anything more than that, then I agree with your assessment.

i am running a single gpu and no oc
works like a charm i can say so but i'd like to improve a bit...

 

[piego59]

question:
u guys know a lot more than me, that's for sure

and i thank u all for ur time

is it worth sliing a gtx 460 or getting new gen video card?

 

[vilenjan]

If already have 460 and can get another for cheap, than sure. Fermis are pretty good at SLI scaling. Just make sure that you buy the same type of 460. If you have the 768 model and you need another 768 model, if its an SE, you need an SE, if its a regular 1gb than you need one like it.
Also the SLI set up will throttle down to the lowest spec card, so if you have a stock card an an OC card, you will need to OC the stock card or both will run at stock (or w/e the lowest of the 2 is).
And if the cards have different coolers, the one with the better cooler should sit on the top of the one with the worse cooler.

 

[piego59]

If already have 460 and can get another for cheap, than sure. Fermis are pretty good at SLI scaling. Just make sure that you buy the same type of 460. If you have the 768 model and you need another 768 model, if its an SE, you need an SE, if its a regular 1gb than you need one like it.
Also the SLI set up will throttle down to the lowest spec card, so if you have a stock card an an OC card, you will need to OC the stock card or both will run at stock (or w/e the lowest of the 2 is).
And if the cards have different coolers, the one with the better cooler should sit on the top of the one with the worse cooler.

it's a gigabyte 460 oc 1gb,
i was thimking about getting exactly the same one what do u think?

 

[COLGeek]

it's a gigabyte 460 oc 1gb,
i was thimking about getting exactly the same one what do u think?

Then you need to budget for a quality PSU as well.

 

[vilenjan]

Good card, you can another one if you dont want the headache, or you can get the Asus, EVGA or the MSi version and try to match the clocks both cards. Out of those cards EVGA has the worse cooling, so if you went for one, that card would be placed at the bottom.