Required current in AMPs for some video cards?

[Wilykat]

I've been trying to look for the power requirement for GTX 470, 480, 580, and 590 but I can't get a straight answer. The number ranged from 25A to 43A but none of the page ever mentions if it is just for the card or for the whole system. The "whole system" rating is useless to me because it never accounts for difference between low end system with bare minimum and no overclocking all the way to high end dual CPU (or quad CPU) server system with lots of bell and whistles and extreme overclocking.

I'd like to add I tried NVidia site but again, I think they used entire system and not individual card as they mentioned 550w for one GTX 470. 550w= about 46amp which seems high for one video card. :/

So I would like to know what are the straight, no BS number just for the power ports on each of the video cards: 470, 480, 580, and 590.

 

[lucuis]

I don't have the exact info you're looking for but i can offer up some more experience related info. I built a machine for a friend that fairly decent for gaming, an 1156 platform iirc. It has a OCZ modxtreme 500w PSU and it has a overclocked gtx 470. And by overclocked i mean not the wimpy factory BS, i did it myself including tweaking the voltage.

Anyone one of those GPUs you listed, except the 590, will run comfortably on a good 500w PSU, even with OCing. With the 590 a good 650w would be plenty.

The power requirements for GPUs tend to be grossly exaggerated by the manufacturer. They do that to cover their own ass. Which is a good thing really, at least a less knowledgeable person will never buy a insufficient PSU if they follow the manufacturer guidelines. It also helps in case the PSU you keep for a long time, capacitor aging will contribute to a less powerful PSU over time (5+ years). So having a bit of an overkill PSU has it's merits.

The 550watt rating for the gtx470 is for the entire system to answer that question.

The TDP of a GPU is a decent number to go by for the power usage of the unit. It's a tad generous, before overclocking, so it's safe to use as an estimate.

 

[unksol]

The number you need to be looking for is TDP. Total design power. This is the amount of power a card is designed to use by the manufacturers. The GTX470 TDP is 215 Watts. 215W/12V = 17.9 Amps. I would give at least a 25% extra to that if its a stock unoverclocked card so 24-25 amps is perfect.

Keep in mind this is JUST the card at stock. It does not consider overclocking, manufacturer overclocking or voltage bumps. The cards drivers also downclock them if they hit TDP but you can override that. As an example my 6950 is 150W TDP card. I unlocked it to a 6970, overclocked it, and bumped the voltage. now it hits the TDP limit and down clocks itself. If I override the limit it will now pull 200 Watts.

You then need to consider you'd CPU (also has a TDP, bug then there's overclocking there too), rest of the system, the fact that you font want to run a PSU at.Max load for a long time, the total 12 rail rating and the fact that many (cheap usually)PSU makers lie about what their PSUs can actually deliver

 

[Wilykat]

Thanks for the info, TDP is what I needed to look for after all. I thought TDP meant thermal design power or roughly the wasted heat output.

So a single 25A rail is enough for one 470. I have a Silverstone 1500w that has 4x 25A rails for PCIe and I currently have a couple 470 sitting around to use for folding. I was planning to add another NVidia card, a single 590 is probably fine with the remaining 2 available 25A rails.

Though I'm waiting to see if there's a release date on dual Kelper (something like GTX 690) but used market for 580/590 is likely to get flooded when new NVidia GPU comes out so I can get either dual 580 or a single 590 cheap.

 

[Sunius]

Thanks for the info, TDP is what I needed to look for after all. I thought TDP meant thermal design power or roughly the wasted heat output.

You can say that as well. You see, that's how electronics work: they convert electricity to heat. The actual power used up for calculations is almost non-existant. Watt is both electricity and heat unit, and that's how much power the card transforms into heat.

 

[unksol]

Thanks for the info, TDP is what I needed to look for after all. I thought TDP meant thermal design power or roughly the wasted heat output.

So a single 25A rail is enough for one 470. I have a Silverstone 1500w that has 4x 25A rails for PCIe and I currently have a couple 470 sitting around to use for folding. I was planning to add another NVidia card, a single 590 is probably fine with the remaining 2 available 25A rails.

Edit: ^ beat my slow phone typing LOL


It might be thermal design power. or used as both. Its 4am and my brain is fuzzy so I am not positive. With a GPU or CPU pretty much all power ends up as heat. its not like a sound amp or motor where your moving something. So either or. Newer GPU designs and die shrinks reduce the power needed to run the chips (reduced resistance is one factor) therefore the heat produced goes down to.

Also keep in mind that rails are a bit of a gimmick. as an example its very common to have 4 25 amp rails which makes you think 1200W BUT have the PSU labeled to only handle 1000W( 83Amps) total at 12V. Your probably only going to pull 800W with 2 470s and a 590 though, but just be aware rail ratings don't equal actual capacity of the 12v source, they are just groups of wires with lower current limiters between them and the actual sources current limiter

 

[jsc]

GTX470 - card needs 15 amps peaking to about 20. A good 550 - 600 watt PSU will be enough.

GTX480 - card needs 20 - 25 . I wouldn't power a system with a '480 with less than a 650 watt PSU.

GTX580 - about the same as a 480.

GTX590 - card needs 30 - 35 amps. I wouldn't power a system with a 590 with less than a 750 watt PSU.

 

[Wilykat]

Best answer selected by Wilykat.