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Do I have enough power?

I

iLLt3cK

Limp Gawd
Joined
Mar 16, 2000
Messages
243
Planning one of the following builds:

Used this link to estimate the power needed:

http://extreme.outervision.com/PSUEngine

Intel Core i3 530 (OC Goal = 4ghz)
Gigabyte GA-H55M-S2H
Sapphire Radeon 4850 HD
4gb Corsair 1600 DDR3
WD 7200rpm HDD
PSU Calc: 292W

AMD Phenom II 555 (OC Goal = Unlock all cores, 3.6ghz OC)
MSI 785GM-E51 Motherboard
Sapphire Radeon 4850 HD
4gb Corsair 1600 DDR3
WD 7200rpm HDD
PSU Calc: 271W


Will my existing Antec 350w PSU work ok for each scenario?

If not - there is a Thermaltake 430w for $20 @ Fry's and a 500w Antec for $35 @ Staples.

Which one would you choose?
 
The 350w would probably be suffice, but I would go with the 430 to be on the safe side, 500w if you are considering future upgrades. That way you are not pushing the system to it's max and ultimately reducing the life expectancy of your components.
 
The 350w would probably be suffice, but I would go with the 430 to be on the safe side, 500w if you are considering future upgrades. That way you are not pushing the system to it's max and ultimately reducing the life expectancy of your components.
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I tend to agree with this here. If that is an Antec Earthwatts at Staples for $35 you can't go wrong, and I would recommend that one. (normally $70-$90 online)
 
Keep in mind the efficiency of most power supplies hangs around 80%. I would go with a higher wattage just to minimize the margin of error.
 
iLLt3cK said:
Will my existing Antec 350w PSU work ok for each scenario?

If not - there is a Thermaltake 430w for $20 @ Fry's and a 500w Antec for $35 @ Staples.

Which one would you choose?
Click to expand...

Unless you have the Antec 350W PSU that came with the NSK1380 case, more than likely you have a very old 350W PSU. A new and good quality 350W PSU would probably have been enough though not at the optimal thermal, noise, and longevity range.

Don't bother with the Thermaltak 430W since it's more than likely just as of low quality as an older Antec 350W. Definitely go with the Antec Earthwatts 500W PSU.
 
Danny Bui said:
Unless you have the Antec 350W PSU that came with the NSK1380 case, more than likely you have a very old 350W PSU. A new and good quality 350W PSU would probably have been enough though not at the optimal thermal, noise, and longevity range.

Don't bother with the Thermaltak 430W since it's more than likely just as of low quality as an older Antec 350W. Definitely go with the Antec Earthwatts 500W PSU.
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I agree with every word of this. Don't bother with that Thermaltake PSU.
 
Just go with the 500 watt as everyone else is saying. When overclocking, power consumption goes way up, the CPU's power usage can reach as high as 150-200 watts, depending on the CPU. A Phenom II x4 clocked above 3.4 ghz will almost certainly hit 150 watts, and an HD4850 will consume another 110-140 watts. Not to mention fans, hard drives, LED's, optical drives, motherboards, you're right up against the limit of your Antec 350 watt, and probably over.
 
Honestly, I'd stop looking at total wattage and watts being pulled off the +12v line/s. Ever notice on a PSU how they have maximum +12v line wattage? You want to take a CPU to about 110 - 130w on a single +12v rail prob rated at 150w @ 80% effeciency not taking into account that that rail will also be powering your motherboard which will probably consume 10 - 20w all by itself by the time you start cranking voltages? I fail to see how literally running a PSU @ near 100% of it's total capacity is a good idea.

There is a lot more to look at than total wattage when it comes to a system. At stock settings it's not such a big deal but when you start talking about OverClocking you are talking about throwing the power spec's way off from their defaults and by the time is said and done almost increasing the power draw of your system by 30 - 40%or more in extreme OverClocking.

Go with the Corsair 400CX or 450vx for the 2 proposed systems as a minimum, the EA500 isn't a bad choice but try to find some place that still has the Seasonic built units.
 
As many people tend to confuse, efficiency plays no part whatsoever in what a power supply can output. Efficiency determines how much the power supply draws at each power output. A 500 watt PSU should be able to put out 500 watts of power, whether or not it is 70%, 80%, or 90% efficiency. It will still be able to output 500 watts, it'll just draw more from the wall with a lower efficiency, and lead to a higher total overall power consumption.

True, the best place to look is at the 12v line, but with many higher-quality power supplies being built nowadays, almost all of the total wattage is available on the 12v line. With the newer DC-DC power supplies, pretty much all but 10 watts of the rated output is available on the 12v line. I wouldn't say he necessarily needs the quality of Seasonic. He is trying to go for budget, and the Antec is perfect for a budget build.
 
Tsumi said:
As many people tend to confuse, efficiency plays no part whatsoever in what a power supply can output. Efficiency determines how much the power supply draws at each power output. A 500 watt PSU should be able to put out 500 watts of power, whether or not it is 70%, 80%, or 90% efficiency. It will still be able to output 500 watts, it'll just draw more from the wall with a lower efficiency, and lead to a higher total overall power consumption.
Click to expand...

I think you might want to look arround the internet just a little. Here is a good example for you to prove/enforce what I said as I think you might be a little confused.

Take the Antec EA 380 for instance. dual 17 amp +12v rails. @ 100% effeciency that would mean 204 watts per rail ( 17 x 12 ), 408 watts total ( 34 x 12 ). Now, divide that by 80% ( .8 ) and you get 326 watts which is only 2 watts off from the 324w Max combined wattage for both +12v rails. This IS how you calculate wattage capacity for a Power Supply.

In the case of the EA380 the rails are split and you cannot put a 130w CPU, a motherboard which will consume 10 - 20w from the +12v rail and each fan you hook to the motherboard will pull 3 - 6w from the +12v rail as well without running the PSU near 100% load on that rail thus destroying the effeciency.

Yes I know the above may make you want to go " But there are 324 watts available on the +12v rail and what you said comes no where near that. You're wrong!. " Well, the rails are split and rail 1 usually power the motherboard and everything connected directly to it like fans, pci cards and processor and too often people forget that the motherboard itself draws power and always to the tune of 10 - 30w on average. The second rail powers your video card and pretty much anything hooked to a molex or SATA connector.

The nice thing about single rail PSU's if when not using a power hog of a video card or a lot of hard drives this leaves you more power to run the core system.

Take the 450VX for example. 33a +12v rail. At 82% effeciency thats the same 324w as the Antec EA380 but it is a lot more versatile as you don't have to worry where the wattage is being used as long as you do not exceed 320ish watts under load although your effeciency at 100% load will be in the 75 - 78% range. You'd have to stay arround 260 - 280w on the +12v rail to maintain peak effeciency.

IF you want a ballsier PSU then aim for something with either single 19a+ +12v rails or a single 40a+ +12v rail. The EA500 gives you a healthy 22a per +12v rail which means an additional 48 watts per rail over an EA380 and that is pretty darned good as it should help keep you near peak effeciency at full load.
 
that is a pretty good explanation of things, but it is also worth it to mention that efficiency also has to do with heat production. the more efficient a power supply is, the less energy is converted (wasted) to heat, per watt of electricity converted.

if a power supply is rated at 500w and 80% efficiency, that means when you start drawing over 400w (80% of total output) the amount of waste heat generated goes up disproportionately in relation to the amount of electricity used. since heat is wasted electricity, that is the point of diminishing returns, where you have to put in more electricity from the wall to get the same amount of power from the computer side of the power supply.

also when you start continuously drawing more then the rated amount of power (400w or 80% in that example), the lifespan of the power supply can be shortened.
 
You would be cutting it close. Definitely upgrade that way you will have breathing room for your PS.
 
compudocs, you're the one who's confused. You really should look up and verify your facts. Efficiency has absolutely NOTHING to do with a power supply's rating. A power supply at 70% efficiency and rated a 400 watts will be able to put out 400 watts, same with a power supply with 80% efficiency and also rated at 400 watts. Now, let me explain how rails work, which you do not seem to understand either.

Let's say we have a power supply, 75% efficiency, 400 watts rated. Now let's say it has 2 12v rails, rated at 20 A each. This means each rail is capable of outputting 240 watts, for a theoretical total of 480 watts. Now, let's say the power supply is rated for 360 watts total on the 12v rails. This means that internal circuitry prevents the two 12v rails from drawing more than 30 amps COMBINED. This is a limitation put in by the manufacturer, not due to efficiency. Additional circuitry prevents the total combined power draw of the 2 12v rails, 5v rail, and 3.3v rail from exceeding 400 watts. This has nothing to do whatsoever with efficiency. These are just internal design limitations and OCP (over-current protection). In fact, often, the OCP does not kick in until you exceed the design ratings by a certain amount. I've seen reviews of power supplies where a 750 watt power supply was able to output 950 watts before it shut itself down. Note, this is OUTPUT, not INPUT from the wall. The efficiency part of a power supply determines how much of the INPUT power is converted to OUTPUT power. A 400 watt power supply with 75% efficiency will draw more than 500 watts from the wall at maximum rated load, while a 400 watt power supply with 85% efficiency will draw less than 500 watts from the wall at maximum load.
 
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@ compudocs
Wow, that whole post is full of bad information and conjecture. But the key problem with your post is this: Efficiency has NOTHING to do with the PSU's ability to provide its rated power. I don't know what internet sources you're using but they're either horribly wrong or you're just not understanding them.

I highly recommend that you read this PSU FAQ:
http://www.jonnyguru.com/forums/showthread.php?t=1036
 
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