Will a 750W psu use more energy than a 650W with the same setup?

[Le_Doken]

Might sound like a weird question. What I'm asking is that for example I have a 650W psu. If I change to a 750W psu, will the psu use more energy (like electricity) or will the 750W psu use the same amount of energy as the 650 since it's essentialy the same setup?

[Oshino Shinobu]

It would depend on the PSU efficiency, not the wattage. 

 

EDIT: But if they had the same efficiency, then in general, no. Though one will be more efficient that the other, depending on the load size. Ultimately, nothing noticeable. 

[Kherm]

No, it depends on the Efficiency rating. 

[W-L]

Might sound like a weird question. What I'm asking is that for example I have a 650W psu. If I change to a 750W psu, will the psu use more energy (like electricity) or will the 750W psu use the same amount of energy as the 650 since it's essentialy the same setup?

 

It's not your PSU that depends on wattage it's mainly the components your running that set how much you'll use, if you get a more efficient PSU however it can lower your wattage from the wall but very marginally to the cost of a higher efficiency PSU like a platinum efficiency one.

[Andrew Storlie]

A computer will ONLY draw the power it needs to run. A computer will run and draw the same power on a 200w psu as a 1600w psu... where the difference comes in is heat and efficiency. Most power supplies have peak efficiceny at around 60% load. So use that as a factor

I always say.... get the largest watt psu you can fit in your case and afford. Say your set up draws 400watts and you get a 450w psu. That psu is gonna run really hot dumping heat into your case and its lifespan is going to be shortened do to heat. BUT if you get a 1000w psu to power a 400w set up, then the power supply can basicly idle power while at load, thus producing less heat and also there for less noise! Im running a set up that draws about 380w and i have a corsair rm1000 psu.... the fan doesnt even turn on. SILENT

[quan289]

Getting a higher-wattage unit doesn't always mean a quieter operation. It depends on the power supply, and as such, if noise level is a concern, it may be best to do research on the noise output of that unit, rather than assuming that a higher wattage unit will be quieter.

 

For example. Remember that a 1000w PSU will run hotter at 100% loads than a 400w unit at 100%. Because of that, a more powerful, thus louder fan would be installed to effectively cool the unit. Take the Supernova 1300w G2 and 1000w G2 for example. Because the 1300w unit has a stronger fan, it had ramp up ~1100 RPM initially, and topped out at over 2000 RPM, whereas the 1000w unit started out at 950 RPM and topped off at ~1500 RPM at 100% load.

 

Also, oddly, unlike the 1000/1300w unit, the lower wattage 750/850w G2 has "Eco Mode". Basically, a switch to turn on semi-passive and fully active cooling - making these two unit quieter at lower loads.