GTX 285 graphs in anandtech review

[tjcinnamon]

This question is prompted from the anandtech review of the GTX 285 power graphs

The graph says full load of the system. This is an i7 with some pretty stacked specs yet the highest total system wattage at load is 490 (with GTX 285 SLi). Why would they bench this with a 1200W power supply?


This brings up the question if I buy a GTX 285 do I need a new power supply. I have an earthwatts 500W power supply already.

I used a Wattage calculator on extreme.outervision.com and it said that my system would consume about 430W of power

3 SATA
1 SSD
Q6600
4 Dimms
GTX 285 (that is why I am calculating)
1 firewire powered device
2 92mm fans
1 120mm fan


The confusion is this seems like a lot of components in the computer yet its only calling for 430W. Yet there are power supplies over 1200W.

Could someone clear this up? Perhaps I misinterpreted the anandtech graphs.

Thanks,
JOe K.

 

[HOOfan 1]

Just because they use a 1200W power supply to do their benchmarking, does not mean that a 1200W power supply is required to run the system. 1200W absolutely is not required to run an average high end system with a GTX 285.

Secondly, I may be wrong, but I believe they do their power consumption tests by specifically stressing the videocard and not the whole system, so theoretically the power draw of the entire system could be higher.

Thirdly, their power consumption numbers are AC power from the wall, since a PSU is not 100% efficient, that means the entire system is actually drawing less DC power from the PSU than the graphs state (note PSUs are rated by the DC power they can output).

Also I don't believe the ExtremeOutervision calculator calculates power consumption, but suggests a PSU for a particular setup. They are not going to suggest a PSU that will output exactly what you need. It is always a good idea to choose a PSU that can output 30%-40% more than you need.

Your Earthwatts should be enough for your system and a single GTX 285. As long as you don't plan to overclock. If you want to overclock I would get something with a little more 12V power maybe 38A-40A...in the 550W range.

 

[smackababy]

Originally posted by: HOOfan 1
Just because they use a 1200W power supply to do their benchmarking, does not mean that a 1200W power supply is required to run the system. 1200W absolutely is not required to run an average high end system with a GTX 285.

Secondly, I may be wrong, but I believe they do their power consumption tests by specifically stressing the videocard and not the whole system, so theoretically the power draw of the entire system could be higher.

Thirdly, their power consumption numbers are AC power from the wall, since a PSU is not 100% efficient, that means the entire system is actually drawing less DC power from the PSU than the graphs state (note PSUs are rated by the DC power they can output).

Also I don't believe the ExtremeOutervision calculator calculates power consumption, but suggests a PSU for a particular setup. They are not going to suggest a PSU that will output exactly what you need. It is always a good idea to choose a PSU that can output 30%-40% more than you need.

Your Earthwatts should be enough for your system and a single GTX 285. As long as you don't plan to overclock. If you want to overclock I would get something with a little more 12V power maybe 38A-40A...in the 550W range.

That statement implies that there are systems that require 1200W power supplies. You'd be hard pressed to find a system that consumes that much power. And I also believe you are correct concerning them stressing the video card alone. What is usually comes down to is quality of the power supply rather than quantity of wattage, for the most part.

 

[theAnimal]

A folding rig with 4 GTX295 or 9800GX2 would require at least a 1200W PSU.

 

[HOOfan 1]

maybe a Skulltrail system with two highly overclocked 9775 Extremes. A high powered TEC for both those chips. All the Ram slots filled, a TEC cooler for the ram. 4 HD4870s . 10 or more hard drives. 5 or 6 fans.

 

[tjcinnamon]

Originally posted by: HOOfan 1
...their power consumption tests by specifically stressing the videocard and not the whole system, so theoretically the power draw of the entire system could be higher.

Thanks very much for your detailed reply,

If you click the link of the graphs it says total system power in watts which is confusing.

If you think a 285 will run with my 500W PSU then I'll try that.

I really can't afford a new PSU right now (nor a 285 but I am weak willed).

 

[HOOfan 1]

Originally posted by: tjcinnamon
If you click the link of the graphs it says total system power in watts which is confusing.

It is the total system draw, but IIRC they use a program that specifically stresses the GPU because that is a better way to compare the power draw of various GPUs. Trying to get the exact power draw of the GPU alone (not including the rest of the system) would require a little more work and some more sophisticated equipment than just a Kil-A-Watt meter.

Since they are focusing the stress on the GPU though, it may not be an accurate picture of real world power consumption. For example, certain games may be stressing both your CPU and graphics card.

 

[VirtualLarry]

Originally posted by: theAnimal
A folding rig with 4 GTX295 or 9800GX2 would require at least a 1200W PSU.

Corrrect

 

[WaitingForNehalem]

Wouldn't the FASTRA be severely CPU bottlenecked?

 

[zagood]

Originally posted by: WaitingForNehalem
Wouldn't the FASTRA be severely CPU bottlenecked?

Looks like the CPU is pretty much just for hand-holding.

This thing is awesome.

-z

 

[smackababy]

Originally posted by: VirtualLarry

Originally posted by: theAnimal
A folding rig with 4 GTX295 or 9800GX2 would require at least a 1200W PSU.

Corrrect

But can it play Crysis at full settings?