How much power do we need?

[gvblake22]

Here's a quote taken from a review of a 1500W PSU published today:

Originally Posted by bit-tech

The thing is: you'll be extremely hard pushed to use anywhere near 1,500W. We tested a 3-way SLI system with a QX9770, 2GB of overclocked DDR3 and three Nvidia GeForce 9800 GTX cards and looped Crysis for a while to warm everything up a bit. An hour later, the PSU is still very quiet yet quite warm to touch, but that's because it was only loaded to ~450W, peaking at 515W. Why do I need 1,100W for 3-way SLI again? Even with eight SATA drives connected to this unit, that'll still be less than 650W at a gross over-estimate.

I know you guys are just kidding about the 1500W PSU thing, this quote was just ironically from a review of a 1500W PSU.

[Reloadron]

Originally Posted by Stormcrow

1500w, thats it? I have a Mr. Fusion hooked up to my rig, and I'm still concerned about overloading the rails and blowing it...it reaches near critical mass when running Crysis as it is.

Damn, I tried for a Mr. Fusion but the NRC shot me down for the permit. Something about a record I had or something. Those bastards! Even tried to get some fuel from DOE and they stopped me.

I was forced to develop an alternate source of power:



Running dual PSUs with a back up in place. Good for 6 KW for about 10 min.

Ron

[polobunny]

Yeah when video card manufacturers say you need a 600W+ power supply, they take into consideration you're going to buy OEM crap. You'd be surprised how often people neglect the power supply in their computer, even though it's just as important as the CPU.
You have to take into consideration that more often than not, the amperage on 12V rails is what will hold you back from upgrading to a Tri-SLi madness and not so much the 5V and 3.3V. We're slowly getting to the point where power supply manufacturers will concentrate more on the 12V (in quality power supplies) but we're far from it when it comes to OEM stuff.
There's also temperature, humidity, dust clogs and age of the power supply you have to take into account. If you live in a hot, humid area, that your power supply capacitors heatsinks are slightly clogged with dust and you've had it for 2 years already, your power supply loses a lot of it's efficiency.

[gvblake22]

Originally Posted by polobunny

Yeah when video card manufacturers say you need a 600W+ power supply, they take into consideration you're going to buy OEM crap. You'd be surprised how often people neglect the power supply in their computer, even though it's just as important as the CPU...
...We're slowly getting to the point where power supply manufacturers will concentrate more on the 12V (in quality power supplies) but we're far from it when it comes to OEM stuff.

Very true, good point. Not all 500W power supplies are created equal! You're probably right in that the video card companies make these statements to cover their asses when Joe Sixpack wants a refund because his 400W "eXtreMe PowMax Demon Gamer Fatal1ty" power supply kicked the bucket and took down the rest of the system after a video card upgrade.

[Smashing]

I have a quality 430w Thermaltake in my current machine. It supports PCI-E, I think it might make the jump.

[azianai]

well i got 3 HDs in my system right now, a 9800GX2, OCing a E3110, 2gb ram OCed, 5 120MM fans and all that jazz, and i only pull like 340W lol. My 520W PSU is still goin strong

[Reloadron]

Originally Posted by azianai

well i got 3 HDs in my system right now, a 9800GX2, OCing a E3110, 2gb ram OCed, 5 120MM fans and all that jazz, and i only pull like 340W lol. My 520W PSU is still goin strong

So what does that tell you? An optical or HDD at spin up draws less than an Amp. Your 5 fans maybe about an Amp. The RAM (even over clocked) draws next to nothing.

The big demand on today's systems is the graphics. That is where the big current demand is on the 12 Volt bus. My workstation which is a monster draws about a max peak of 600 Watts at the wall outlet on boot. Then settles down to less than 500 watts when working.

Ron