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Are amps and rails important for GPU?

Tags:
  • GPUs
  • Power Supplies
  • Power
Last response: in Graphics & Displays
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July 19, 2014 12:02:18 AM

Hi,

Normally i would check total number of watts on a power supply to determine if its enough to power up a PC including the most power-hungry components CPU and GPU.

Ive been reading on the net and i see posts that talk about how amps on the 12v ( im assuming the 12v is used by the CPU and GPU) and if its enough to provide the gpu. I don't really understand all this.

I'm using an Antec EA750W, and lets say i get a GTX 770 which according to Nvidia requires a minimum recommended system power of 650w and the card power is 230W
http://www.geforce.com/hardware/desktop-gpus/geforce-gt...
But there's no mention of amps anywhere.

Just need to have a better understand at this, im no computer scientist :) 

And about single rail and multi-rail, should i be worrying about these too?



More about : amps rails important gpu

a b ) Power supply
July 19, 2014 12:09:41 AM

I believe that the rails are sometimes different so it can be 8 Volt and $ Volt Rails, which add up to 12, the rails matter because if the rails were not balanced properly in terms of power, then if you try to overclock it there will be instability.

'NVIDIA are supporting the overclocking community even further with an advanced three rail PWM with load balancing, whereas older GTX 780 and Titan pulled all their power through three rails, they did not load balance. 780Ti's new PWM means it can source power from three sources and load balance resulting in the same amount of power from each rail, allowing for more superior overclocks and stability.'

This is a quote from a review about a 780 ti about how the manufacturer has improved in its power draw.

About the PSU quesion, the suppliers recommend that amount as they don't know what rig or components you own so they suggest a 650W PSU so you won't have to worry about it not being powerful enough and sothaht if you OC, your card won't stop
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July 19, 2014 12:15:21 AM

Ok but i wont be overclocking, Id still be fine yeah?
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a b ) Power supply
July 19, 2014 12:18:10 AM

Daconstaz said:
Ok but i wont be overclocking, Id still be fine yeah?


Yeah but just make sure that you have the minimum recommended PSU voltage so you won't run into any problems
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July 19, 2014 12:33:22 AM

Yes, amps are important. If your PSU doesnt have enough amps on the 12v rail, and you try to run a GTX 770 for example, which needs 42A (Source), it may cause your CPU to overheat, or even catch fire.

Your PSU has four +12v rails, that can each provide up to 40A. So you should be able to run a GTX 770 fine.

Have a look here to find out more about Single rail and Multirail: Single rail vs Multi rail explained
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July 19, 2014 12:34:53 AM

Thanks

On my PSU label it shows 4 12V and under each it shows 40A. Basically im trying to understand this and what it means


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July 19, 2014 12:35:37 AM

bradsctt said:
Yes, amps are important. If your PSU doesnt have enough amps on the 12v rail, and you try to run a GTX 770 for example, which needs 42A (Source), it may cause your CPU to overheat, or even catch fire.

Your PSU has four +12v rails, that can each provide up to 40A. So you should be able to run a GTX 770 fine.

Have a look here to find out more about Single rail and Multirail: Single rail vs Multi rail explained


Thanks
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July 19, 2014 8:35:22 AM

Just curious, How do you calculate the the amp requirements. Is it TDP / 12 ? where for a 770 TDP is 230
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a b ) Power supply
July 19, 2014 8:42:59 AM

To find out how much wattage equals from voltage and amps, you multiply the amps and voltage together.
42 Amps on 12V rails = 504 W roughly.
What power supply do you have exactly?
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July 19, 2014 4:35:23 PM

He said up further = Antec EA750W
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a b ) Power supply
July 19, 2014 4:38:31 PM

bradsctt said:
He said up further = Antec EA750W


There are different versions.
This statement makes me question what actual psu he has:
"On my PSU label it shows 4 12V and under each it shows 40A"
This is not a 750W power supply with these specs
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July 20, 2014 4:27:44 AM

Suztera said:
bradsctt said:
He said up further = Antec EA750W


There are different versions.
This statement makes me question what actual psu he has:
"On my PSU label it shows 4 12V and under each it shows 40A"
This is not a 750W power supply with these specs


Actually you have a good point there.
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