System Builder Marathon, Q3 2013: $650 Gaming PC

[AtariST]

How did you get all of these components to run on a 450W power supply much less OC? Asus and Corsair PSU calculators recommend 600-650W PSUs without over clocking. Are we grossly overbuying? Are we being grossly over sold?

 

[InvalidError]

How did you get all of these components to run on a 450W power supply much less OC? Asus and Corsair PSU calculators recommend 600-650W PSUs without over clocking. Are we grossly overbuying? Are we being grossly over sold?

For the most part, yes, PSU "requirements" on GPUs are grossly inflated.

Even the most powerful single-GPU systems usually draw less than 400W PEAK and 300-350W average at full-load measured at the wall. With a 90% efficient PSU, that means about 360W total peak PSU output load so in theory, a high-quality 400W PSU should be able to run just about any single-GPU system save for the most crazy over-volted overclocks.

The problem is that there are tons of sub-par PSUs out there that will croak prematurely at loads well below 100%... or even 50% in many cases. So, GPU manufacturers try to "compensate" for that by drastically inflating their "requirements."

 

[Traciatim]

How did you get all of these components to run on a 450W power supply much less OC? Asus and Corsair PSU calculators recommend 600-650W PSUs without over clocking. Are we grossly overbuying? Are we being grossly over sold?

Absolutely 100% yes. It's purely marketing that sells high wattage power supplies. Even a 3770k highly overclocked running with a nice new 780ti that was released recently only pulls about 410 watts from the wall (Review from HardOCP) . . . that means the PSU was supplying the machine with about 370 watts (since it was about 90% efficient).

It is extremely rare that a machine actually requires more than a 500 watt power supply, and generally it's only when you are building a machine with two high end video cards.

The main problem is that if you manufacture video cards and you say it only needs 200 watts then someone is bound to run it on some cheap piece of junk supply that will melt and then complain that you said it would run. So manufacturers have to grossly over-recommend in order to ensure it covers all the cheap junk supplies out there.

 

[Outlander_04]

I do not believe its just a matter of marketing trying to upscale people into higher wattage PSU's .

Firstly the rated wattage of many cheap power supplies is some random figure that their marketing department decided to use .

Secondly even reputable brands sometimes rate using high current draws on the 3.3 and 5 volt rails . Rails that have nothing to do with powerful graphics cards . [ Its always best to check the amperage on the 12 volt rail . A x V = W ]

And finally if a computer uses 450 watts and you use a 450 watt psu this is the same as running your car at full speed . It will not last as long as if you were running it in the 50 - 60 % load range [ which tends to have the highest efficiency in most psu's too ]

 

[InvalidError]

Secondly even reputable brands sometimes rate using high current draws on the 3.3 and 5 volt rails.

ATX 2.xx compliant PSUs are designed to deliver most of their power on the 12V rail(s) and from a cost-cutting perspective, high current on 3.3V/5V rails is also more expensive than on 12V rails since below 20V or so, current is a much greater factor in costs and efficiency than voltages.

PSUs with high ratings on the 3.3V/5V rails usually follow the ATX 1.xx spec and should not be used in modern PCs.

 

[youssef 2010]

According to your graphics card hierarchy chart, the 7870 LE and the 760 share the same level of performance. But in this SBM you say that the 760 is superior. Is there something wrong with the chart or is there another reason?

 

[eminemmanjit]

can these settings play bf3,mw3 on ultra and cod ghosts on mid/high???