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how do you calculate your system power requirement?

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wolfio

Member
Joined
Mar 14, 2003
Location
Beaverton, OR
Been looking arround but found no definite answer.
My system is
1700+ Oced to 2.5ghz @1.85
radeon 9700
512MB of RAM
2x120GB HDD 720rpm
1x DVD-ROM
1XCD-RW
8rda+ using onboard sound and NIC.
3.5" Floppy
6x 92mm FANs (low rpm)
3x120mm FANs (low rpm)
just wondering what's the total power requirement of this spec.
which power supply that will give a bit of room? antec tru power 430W enough?
thanks in advance.
 
Check out this list from THG.

I've used this so much (mostly for posts like this) that I've dropped it into my favorites folder. It breaks down just about everything you could possibly want to put in your system and gives the power demands for each.

One note: The power total listed are for the total number of such components used in this system. For example, there are four hard drives in this rig and the total draw is 112 watts, or 28 watts per drive.

And Skab, since everything short of a Tornado will use less than five watts you probably have enough power for a lot of fans. ;)




BHD
 
I basically use a quality psu.

If I am building a budget system, I'd go for like 350w, but if I was building my "gaming" machine I'd have like a 450w quality psu.
 
Ok after doing a bit of searching on each of my componenents power req. hers' what i got
Total power I need is 359Watt +/-
3.3V Total = 10A
5V Total = 20.2A
12V Total = 18.8A

Btw--you guys have any idea how much Wattage power @ 12V line a xp1700+ running 1.85 2.5ghz draw?

Antec TruePower 430 have 12V 20A rating - is that mean If I were gonna use it for my system - it will be barely enough?
 
Could you list what is going into this box? Getting close to 400w is a lot of juice. Are you going to be running a phase-change or pelltier cooling set up?

Overclocking doesn't increase power draws enough to create a problem. If you were overloading your PSU you'd know it well before you overclocked your proc or video card.



BHD
 
6x92mm fan
3x120mm fan
3x40mm fan
1x80gb wd 8m hdd
1x120gb ibm hdd
1cd-rw
1 dvd-rom
floppy drive
512mb ram
onboard sound/nic
9700 ati radeon
keyboard/nouse
2 usb device


that's about it
my question do tbred draws power from 12v line or 5v?
coz according to tomshardware site--it's listed to draw from 12v line..?
 
it comes down the 12v line

and 20amps on the 12 volt line is 240 watts

2100+ at stock uses 90
 
I just added up what you listed and came up with a liberal estimate of 333 watts for everything in your system, and that is when everything is running simultaneously.

That's about what I suspected. Even with watercooling, its tough to pull 400 watts on a desktop system. Servers and SMP boxes with large numbers of hard drives are another matter. But for a single proc desktop system, you have to cram a lot of gear inside to make a good 400W PSU sweat.

Notice the word good. A lot of PSU makers hype peak power levels but don't deliver. A good PSU will actually be able to deliver the advertised power at the peak of the listed operating conditions. My PC Power and Cooling Turbo Cool 450 is guaranteed to deliver 450W at close to 120 degrees farenheit. At room temperatures its actually good for close to 530W.

A cheap PSU will hit its advertised output once in the lab. It's easy to buy a "400W" PSU that can't make over 250W at gunpoint. The key is picking a brand with a good reputation for quality. Sparkle/FSP is my pick for a PSU under $100, and PC Power and Cooling if your budget is over a c-note. I guarantee a Sparkle/FSP or PCP&C 400W PSU will do the job for what you are putting in your system and have power to spare. Antec? Some people around here love them but the defect rate is too high for me to endorse them. You do not need a 500W PSU-period.

One last note about your fans: There is a point in every air cooled setup where adding more fans or volume only increases the noise. I don't know what kind of case you're going to use, but I strongly suggest what you have listed is way beyond that point of diminishing returns. You might want to think about starting with fewer fans and adding them until you find the best balance between noise and performance.





BHD
 
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