Is 850 Watt enough for 2x R9 290x GPUs?

[davidst99]

Hi,

I have a SeaSonic 850W PSU. Is it enough to power an overclocked I7 4770K, 2x R9 290x GPUs (factory overclocked to 1040Mhz), 1 SSD and 2 HDDs?  If not, how big of a PSU would I need? I searched Google and everyone has a different opinion about how big your PSU should be.   Thanks for any help.

David

[Shd0w2]

Yes

[alexdenseje7]

i think that going with over 650W is for more then one GPU and 750-850 whould be fine (850 bettere) for sli/crossfire

 

and don't listen to the ones that say "Nooo get a 1200W it will be bettere"

[davidst99]

Ok, thanks for the help!   I'm glad I don't have to buy a new PSU.

 

 

David

[LawrenceBarnes2013]

800+W 80+ Gold, hell yeah

[atrash]

absolutely.

[daemonowner]

800+W 80+ Gold, hell yeah

ftfy. Efficiency doesn't affect the power delivered, but rather the power drawn and lost from the wall.

 

@davidst99 Which model is your PSU? It's Seasonic, so I imagine it's capable of delivering the full 850W, so you should be good.

[davidst99]

Hi, daemonowner, sorry for the delay.  I have the SeaSonic X Series X-850

 

http://www.newegg.com/Product/Product.aspx?Item=N82E16817151102&cm_re=seasonic_850-_-17-151-102-_-Product

[daemonowner]

Yep, that's great.

[TriBeard]

You should be fine. If you were buying a new PSU anyway, I might encourage a 1000w just to give a little more headroom, but since you've already got the 850w just use that. Being that it's a good brand and could almost certainly output all 850w if it needed it, I'm fairly confident you'll be fine.

[LawrenceBarnes2013]

ftfy. Efficiency doesn't affect the power delivered, but rather the power drawn and lost from the wall.

 

@davidst99 Which model is your PSU? It's Seasonic, so I imagine it's capable of delivering the full 850W, so you should be good.

i wasn't talking about the power delivered, talking about the PSU wattage delivery reaching it's 80% with CF 290X needs to have Decent efficiency to keep up with the wattage need and by that last longer at rated efficiency

[daemonowner]

i wasn't talking about the power delivered, talking about the PSU wattage delivery reaching it's 80% with CF 290X needs to have Decent efficiency to keep up with the wattage need and by that last longer at rated efficiency

I don't understand.

[LawrenceBarnes2013]

I don't understand.

let' say it's some random 80+Bronze, when it reaches the 80% Power delivery that's when the efficiency comes in but being rated at Bronze, if it keeps on delivering 80% of the wattage it can deliver for so long, it will start to slag behind and die soon, but when the PSU is rated at Gold/Platinum... it can deliver that 80% and more for long without loosing any of it's performance, so using two 290s will nedd at least a 750W, and drawing that much power constantly needs a PSU Efficiency that can handle it for long

[daemonowner]

let' say it's some random 80+Bronze, when it reaches the 80% Power delivery that's when the efficiency comes in but being rated at Bronze, if it keeps on delivering 80% of the wattage it can deliver for so long, it will start to slag behind and die soon, but when the PSU is rated at Gold/Platinum... it can deliver that 80% and more for long without loosing any of it's performance, so using two 290s will nedd at least a 750W, and drawing that much power constantly needs a PSU Efficiency that can handle it for long

 

So what you're saying is Gold certified power supplies will tend to live longer than Bronze certified power supplies. Efficiency is a rough measure of quality, so this is kind of true. However I'm not convinced a Bronze certified power supply is going to fail to deliver the needed power ('lose its performance') and soon die. Even if you mean a few years. A decent 750-850W Bronze power supply could power dual 290's for years. It's fine.

 

Also where did the "80% power delivery" come from? Would the same not be true for a 750W power supply running at 50% load for several years? What about 100%?

What does "the efficiency comes in" mean?

[LawrenceBarnes2013]

So what you're saying is Gold certified power supplies will tend to live longer than Bronze certified power supplies. Efficiency is a rough measure of quality, so this is kind of true. However I'm not convinced a Bronze certified power supply is going to fail to deliver the needed power ('lose its performance') and soon die. Even if you mean a few years. A decent 750-850W Bronze power supply could power dual 290's for years. It's fine.

 

Also where did the "80% power delivery" come from? Would the same not be true for a 750W power supply running at 50% load for several years? What about 100%?

What does "the efficiency comes in" mean?

a 750W PSU converting it's input to 500W, that is about 65% of it's total delivery, and let's say it's not even 80+ certified, it's fine because it's not near the efficiency Mark, but once there, it will start to fade, that where efficiency comes from, itch PSU is tested and see how stable it is when delivering Near it's peak wattage, and yes a Bronze certified PSU of 750W will handle 2x290s but not for so long, that's why people recommend High quality/Efficiency  PSUs when doing an extremely wattage demanding build 

[Sauron]

Ok, thanks for the help!   I'm glad I don't have to buy a new PSU.

 

 

David

mark the thread as solved then. All you need to do is click on the "best answer" button on, well, the best answer.

[daemonowner]

a 750W PSU converting it's input to 500W, that is about 65% of it's total delivery, and let's say it's not even 80+ certified, it's fine because it's not near the efficiency Mark, but once there, it will start to fade, that where efficiency comes from, itch PSU is tested and see how stable it is when delivering Near it's peak wattage, and yes a Bronze certified PSU of 750W will handle 2x290s but not for so long, that's why people recommend High quality/Efficiency  PSUs when doing an extremely wattage demanding build 

What....?

 

Converting it's input? A 750W power supply that supplies 500W to the components will draw [500W / efficiency] from the wall. Lets say it was 80% efficient at 66% (500W) load. That means it would draw 500/0.8 = 625W from the wall, 125W of which would be lost, mostly as heat, and 500W would be delivered. Efficiency mark? You think 80% is an efficiency mark where "the efficiency comes in"?

 

So, imagine we have a non-80Plus certified power supply. Drawing 65% of what it can deliver is fine, but drawing 85% of what it can deliver is not fine? Because it isn't 80Plus certified?

So, imagine we have a very efficient power supply. 80Plus Platinum. Drawing 65% of what it can deliver is fine, and drawing 85% of what it can deliver is also fine, because it is platinum certified?

You don't understand 80Plus ratings and power supply efficiency at all.

 

A high quality Bronze certified power supply can run 2x 290's for quite a while. Years. Easily. The quality matters more than the efficiency.

[atrash]

daemonowner, on 16 Jun 2014 - 6:03 PM, said:

-snip-

So persistent. Go preach them,brotha..

[Wyre]

http://www.extreme.outervision.com/psucalculatorlite.jsp

 

I have found this to be a very valuable tool. Just plug in the required hardware and click the 'calculate' button.

[AllstaRawR]

I should be able to run that with my HX750. Barely. So you'll be fine.