520W not enough power?

[vexeus]

I have a SilverStone ST52F PSU with 31A on the 12V rail.

I went through the PSU calculator here for a system I'm building that should be finished this week (see sig).

Anyways, I assumed I would overclock the opty 165 to about 2700 if I were lucky on 1.55V (worst case scenario I figured) and that was 218W. Then adding in the X1900XT I'm already up to 600W? Is that an accurate estimate?

Only reason I ask is because ATI only recommends a 450W PSU for their X1900XT, but this already has me up to 600W, which is clearly more than my 520W can handle.

I DO have a standby PSU that I did not want to use since it's considerably more noisy than the 520W one... the SilverStone ST65ZF (650 Watts). But even this PSU seems to fall short once I add in 2 SATA drives, 2xDDR ram, a DVD drive, and a soundcard.

What's the deal? Is this just taking the worst case scenario and I shouldn't be worried? Can I still use the 520W without worrying about it holding back my system or do I have to go with the noisier 650W?

 

[Asian Dub Foundation]

ur psu will be fine

dont bet everything on the psu calculator

 

[vexeus]

I've seen benches showing the X1900XT sucking up 300+ watts, and then add to the fact that the 165 is 110W without overclock... then the 520W ST52F has only 372W on the 12V rails...

Are you sure it's gonna be enough? Blargh I'm so confused.

 

[jonnyGURU]

An X1900 does not suck up to 300+ Watts. The PSU requirements for running two in Crossfire is only 38A (456W) on the combined 12V rails. That a lot of juice, but certainly not 300+ W per card considering ATI is leaving overhead for CPU, drives, etc.

 

[LstBrunnenG]

I've seen benches showing the X1900XT sucking up 300+ watts, and then add to the fact that the 165 is 110W without overclock...

That's a system power draw, killer, not a video card power draw.

 

[FreiDOg]

I've seen benches showing the X1900XT sucking up 300+ watts, and then add to the fact that the 165 is 110W without overclock... then the 520W ST52F has only 372W on the 12V rails...

Are you sure it's gonna be enough? Blargh I'm so confused.

I'd bet dollars to doughnuts that you've seen systems running the X1900XT drawing 300+ watts from the wall.
The XTX card itself needs about 120W.
(XT would be slightly less, probaly not much).

 

[needmorecarnitine]

I went through the PSU calculator here for a system I'm building that should be finished this week (see sig).

Anyways, I assumed I would overclock the opty 165 to about 2700 if I were lucky on 1.55V (worst case scenario I figured) and that was 218W. Then adding in the X1900XT I'm already up to 600W? Is that an accurate estimate?

If what you posted is correct,

that is probably the worst psu calculator I have ever heard of

 

[vexeus]

Ahhh, makes sense now. Thanks for clearing that up everyone. What I was looking at was total power consumption, not just the X1900

Alright, now I know not to trust that calculator. Thanks again.

 

[Ice Czar]

If what you posted is correct,

that is probably the worst psu calculator I have ever heard of

which is why we miss takaman's so much
any calculator not busting out the amps per rail is more or less a feel good device than a useful tool

Id say do it manually
http://www.jonnyguru.com/PSUInquisitor/
http://jonnyguru.com/findingtherightpsu.html
http://users.erols.com/chare/elec.htm
http://www.xbitlabs.com/articles/video/display/gpu-consumption2006.html
http://hardforum.com/showthread.php?t=844691

The XTX card itself needs about 120W.
(XT would be slightly less, probaly not much).

http://www.xbitlabs.com/articles/video/display/gpu-consumption2006_4.html

108.67W or 9A +12V

watts \ volts = amps
amps x volts = watts