Power supply requirements overhyped?

[omber]

My system specs are below add 2 hard drives and single optical drive, the case has four fans of its own. When I was buying the 8800 GTX I was informed that minimum power supply required for them should be 650 Watts. I've never taken interest in the power requirements of gaming rigs so I decided not to argue and just paid up. Yesterday my buddy brought over his Watts Up, and we quickly plugged it in to take a look.

While idle/doing desktop work the computer draws about 175 Watts of power, while playing games (We tried Crysis and TF2 to see if it makes difference) it goes up to about 420 W.. Is it me or are we all suckers and overpaying for massive power supplies we don't need?

 

[HOOfan 1]

Well the system actually uses the most power on startup.

Who informed you that you needed a 650 Watt power supply? Most 8800GTX manufacturers sated the requirements of the 8800GTX as a 400-450watt PSU with a combined amperage of 30A on the 12V rails.

As has been stated before, once you get to the point where you are buying quality components to build a PSU, these components are expensive enough that you may as well built a 550W+ power supply to justify their cost.

 

[mpilchfamily]

The recomendations are from the manufacture of the cards. They are set high to cover the power needs of just about any system those cards will be used in. Also keep in mind that cheaper PSUs Don't supply as much of there total power to the 12V rails as some better quality units will. So you would need a higher wattage cheap PSU to give you the amperage needed on the 12V rails to support your system.

Yes a good quality 500W PSU would support your system fine. You havn't mentioned what PSU you have so we don't know if that model is really overkill or not. It may be that you had to get a 600+W version of that model in order to have enough amperage on the 12V rails to support the system and leave some head room for its peak power draw.

 

[omber]

I guess I should have researched it on my own .. oh well though I will remember this for next time, and it does not even go near the peak gaming power at startup. Interestingly, friends rig draws about 103 Watts when.. off ?

 

[MarcVenice]

Erm, if you see a powerdraw of 420w for sustained periods of time, then you actually should be HAPPY with your 650w PSU. Why ? if you had a 500w PSU you'd be running your PSU at 80% of it's capacity, if not a little higher. That's not the sweetspot for a PSU, the PSU fan will ramp up, create more noise. The hotter your PSU gets the shorter it's lifespan. I must say though, 420w for your system sounds a little high.

 

[mpilchfamily]

My guess is he had his power strip plugged into the meter and not just the tower.

 

[HOOfan 1]

and still he would be measuring AC power draw, and not DC power output....and I think we can all assume his PSU is not 100% efficient. $20 watts of AC is probably about 330 Watts of DC