Which part uses most power?

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brutalizer

[H]ard|Gawd
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In power usage diagrams, we typically see 76 Watt for Ivy Bridge system.

But is there information how much watt each part uses? For instance, how much does RAM use? How much does power supply use? etc? Then we can optimize lower wattage. For instance, if cpu is only using 5Watt in idle, then look elsewhere for optimizing.
 
There are tons and tons or resources all over the web to answer your question on power use per component. Lots of white papers and spec sheets for just about everything. Oh, and power supplies don't use power, they provide it by converting the type of power at the wall outlet to the type of power the components need (120V AC to 12V DC). Well, they do use a little, from electrical losses in the components they're built with, but it's rather small.
 
I thought power losses from power supplies was somewhere around 7% to 30% which would not be insignificant.
 
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So... anybody knows which parts are the most power drawing? Is it the mobo? I heard each memory stick uses 5-10 Watt. If you have 4 sticks, it is 40 watt. Then it is better to keep the number of memory sticks down. Sandy bridge and Ivy Bridge use 10W in idle, I guess. An harddisk use 5-10 Watt under load. An SSD use 1 Watt. etc. Can you fill this list in? And if I am wrong, please correct me.

-RAM memory stick: 5-10 watt
-Hard disk: 5-10 watt
-Sandy bridge/Ivy bridge at idle: 10 watt
-Modern Nvidia graphics card at idle: 15 watt

What is left? How much does a mobo draw? An PSU?
 
someone will probably be able to explain it better but all PSU's use more energy than they can efficently convert to 12v power for your PC.

E.g a 1000w 90% efficent power supply that needs to supply a computer with 500w will pull 556w from the wall - the extra 56w is waste. If you use a 1000w 80% efficent power supply you need to pull 625w from the wall. It therefore pays to get the most efficent power supply of the size you need that you can afford
 
Fans can pull anything up to 12-15w each depending on size and power
 
It therefore pays to get the most efficent power supply of the size you need that you can afford
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Yes. Exactly. Depending on the power supply design you may get more efficiency by getting a lower rated model that better fit your expected idle and full load. For example if you have a 40W idle machine you could be wasting a significant amount of energy if you used a 1000W 80 plus supply because at 40W this is way less than 20% where the supply is rated at 80% efficient. Below 20% the efficiency is not guaranteed to be 80%.
 
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Fans can pull anywhere from 1 watt to 30 watts. Depends on whether you have slow running fans (less than 2000 RPM), high speed fans (more than 3000 RPM), and LEDs.

In most scenarios, the motherboard, RAM, add-in cards, extra USB stuff, fans (at most 5 slow LED fans), and hard drives (at most 4) are safely estimated by 50 watts.

Modern motherboards do not use as much power, due to the northbridge now being integrated into the CPU. X58 was a monster power hog, especially at idle, partially due to the X58 northbridge.

In most scenarios, it doesn't pay to get the most efficient power supply, if looking at a power cost savings standpoint. It will take more than 5-10 years in general to recoup the costs of buying a better power supply, for normal usage. The usual reason to get a more efficient power supply is because the more efficient power supply generally has better internals.

Hard drives while idling can use less than 2 watts, due to green power technologies spinning down the hard drive.

A PSU does not draw power. It wastes power in the form of heat during the conversion of AC voltage to DC voltage. That's what the efficiency ratings are for. Although, it can be argued that the active PFC circuit does use power, but its generally miniscule.
 
By far the graphic card pulls the most power. Of course, it also depends on which graphic card you are referring to. The Radeon HD 6990 draws a maximum of 404w of power. But if you have a Radeon HD 5450, then the max power draw would be 14w so it would be one of the less power hungry component in a PC.

The CPU is typically the 2nd most power hungry component; at least in a gaming PC. How much power depends on the which CPU and if it is overclocked.

The motherboard is likely the 3rd most power component. It probably ranges between 30w to 70w. It depends if you are talking about a basic mATX mobo with not a lot of bells and whistle to a premium extended ATX mobo with lots "premium" features.

Overall, the single component that can help reduce your total power consumption is the power supply. The basic recommendation is to by a PSU that is rated at 80PLUS which generally means at any given load the PSU will be at least 80% efficient. Then there's the "medal standard" ranging from 80PLUS Bronze (82%) up to 80PLUS Platinum (90%). I believe non-80PLUS certified PSUs generally have an efficiency ranging between 55% - 75%
 
So if I use an 200 Watt GPU, and 70 Watt CPU, then I can expect a total of 200 + 70 + 50(mobo + disks + stuff) = 320 Watt usage.

Then I should get an 80+ PSU operating at 350Watt. To buy 1000Watt would waste lot of wattage, because it does not operate in it's optimum range? I dont really understand this.

If I had 1000Watt PSU to pull 100 Watt idle, then it would use 100 / 0.9 = 111 Watt. That is, 11 watt is waste.

If I hade 200Watt PSU to pull 100 Watt idle, then it would also use 100 / 0.9 = 111 Watt ???

Or have I misunderstood things?
 
brutalizer said:
So if I use an 200 Watt GPU, and 70 Watt CPU, then I can expect a total of 200 + 70 + 50(mobo + disks + stuff) = 320 Watt usage.

Then I should get an 80+ PSU operating at 350Watt. To buy 1000Watt would waste lot of wattage, because it does not operate in it's optimum range? I dont really understand this.

If I had 1000Watt PSU to pull 100 Watt idle, then it would use 100 / 0.9 = 111 Watt. That is, 11 watt is waste.

If I hade 200Watt PSU to pull 100 Watt idle, then it would also use 100 / 0.9 = 111 Watt ???

Or have I misunderstood things?
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I think what it is saying is that your power rating (80 PLUS would = .8 and Platinum = .9 where 1.0 represents 100% Efficiency and those previous two represent 80% and 90%) is very efficient then you'll have to pull less energy from the wall and less will be lost from heat so for example.

If all your components sucked up 450W under FULL LOAD and it was 80 PLUS = .8 then you'd divide 450 / .8 = 560W would be needed to power the 450W system at full load. 560 - 450 = 110W more your PSU is pulling from the wall meaning you lose 110W of energy to heat that never gets delivered.

Math makes my head hurt and I may be wrong. Someone will eventually correct me if I am.
 
Rule of thumb when buying a PSU is to get 100 or so watts over your required amount. Not to mention the ratings of wattage on Power supplies are not what will be drawn from the wall. The Power supply only draws what it needs so if your system needs 400 watts and you have a 1000 watt power supply then it will only draw 400 watts Plus the wattage it wastes (if you didnt already know this).

One other thing to note is that a lot of power supplies with bronze silver gold and platinum efficiency ratings will only perform at that given efficiency at a given supplied wattage. For example
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Here is a review done by the guys at Hard (thanks for the review) as you can see this 1200 watt gold rated PSU is at 90 percent efficiency at 612 watts while when it draws 1200 it is at 86.71 efficiency at 1200 watts
I hope that makes sense

If I were you I would not worry so much about the efficiency of the psu (look for an 80 Bronze or better, because, like someone above said, the more efficient power supplies are more efficient because of the quality of the components (usually) ) I would then look at how much "ripple" the power supply has and chose from there.

As per your original question...(I sort of forgot your original question and whet off of your above post :eek:) You can look up fact sheets on all of the parts you need online.
 
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