Power Supply Reference: Consumption, Savings, And More

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palladin9479

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Holy cow. Thanks for that Asus PSU link. I now know what's causing my system instability.

AMD Phenom II x4 980BE OC'd
4 x 4GB DDR3-1600 memory
2x NVidia GTX-580 SLI'd
4x SATA HDD's
1x SATA DVDRW
7x FANs (Water cooled system)

Comes to 1150W recommended. I have a Corsair HX-1000 1000W PSU.
 

sincreator

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Still running a Thermaltake 750w toughpower here. Been 5/6 years now. Man this PSU has seen some upgrades. lol. I'll probally buy another toughpower/Corsair sometime in the near future.(If this one ever dies. lol)
 

Dacatak

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Still using the same Enermax Liberty 500W from 2006 for my new Sandy Bridge upgrade with GTX 560Ti.
The only reason you'd need more than 500W is if you need to power more than one GPU.

Of course, as stated in the article, not all 500W PSUs are equal. The Enermax Liberty was among the best 500W PSUs in its day, and its quality is still exceptional even by today's standards.
It has dual 12V rails with 22A on each with a combined output of 32A total. Most of the dual-rail 500W PSUs sold nowadays max out at 18A per rail.

The Enermax was definitely ahead of its time, and in general, PSUs sold directly by their manufacturer (OEMs such as Enermax, FSP, Kingwin, Seasonic) tend to be of superior quality than those sold by third-party rebranders (Antec, OCZ, Thermaltake, Corsair, etc.).
 

cumi2k4

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Was wondering about power cycling and thermal shock... The article said that thermal shock from powering on & off can cause deterioration in a system. You suggest S3 (Suspend to Ram), but does this also cause thermal shock to the system when resuming from sleep mode?
 
Great article and thanks, it'll 'hopefully' make my job easier in the Forum and stop the silly arguments I have recommending PSU's. I really wish folks would stop skimping on their PSU's on nice systems.

Another important point that folks have a tendency to forget is 'electrolytic capacitor aging' which over time takes their once 650W and after a year or so reduces it to 520W~500W aka Capacitor Aging.

Great PSU Sizer -> http://www.thermaltake.outervision.com/
Peak:
100% CPU Utilization (TDP)
100% System Load
30%~35% for Capacitor Aging
 

zak_mckraken

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@cumi2k4 and lordvj : We can only assume it does cause a thermal shock, since only the RAM retains power in S3 mode. The other unpowered components thus cool down during stand by mode, like a regular shutdown.

Very informative article by the way!
 

TeraMedia

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@palladin9479:

Yeah, me too! I had significantly underbudgeted power for fans (9), ODD/HDDs (8) and USB devices (3), and was going nuts trying to figure out why the system was unstable at times. I thought I had a bad MoBo, or HDDs, or GPU, or ??!?!@#$? Now I know.
 

xenol

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I'm kind of suspect about the ASUS power supply link. It tells me for my old system, I should get a 600W power supply but I ran a 500W on it for years without problem.
 

Onus

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The statement about third party rebranders depends on who the OEM is. If Seasonic or Delta makes it (e.g. most Antec units), it is going to be a good PSU. Many Corsair and XFX are made by Seasonic too. Channel Well, Sirtec, and some others have some units that aren't so great.

I found the article of some interest (and will revisit the sleep settings on my own system), but some of it was also years out of date. That's probably hard to avoid on a writing project of this magnitude.
 

chaz_music

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Good collection of interesting PSU topics. I especially liked the ACPI information. I have several comments and suggestions to change in the article though. I work in the PSU industry and can shed some light on a few issues.

On efficiency, most people leave out the fact that we tend to use air conditioning here in the USA a good part of the year. Here in the mid Atlantic, we tend to use A/C for about ~ 7 months annually. This adds a thermal penalty to any heat that you dump into the office/home air during those months. With most A/C systems, the cost to remove 1W of heat is an additional 0.5W of A/C power (50% overhead). Taking the above numbers and some rounding, I use an overhead rating of 30% total for any heat dumped into my home / office. So take your power loss numbers and multiply by 1.30 to get the total cost impact to your wallet. This also should be done for using CFL and LED lighting. They are not allowed to use A/C cost in their advertising, so the public does not get to see the true possible savings.

There are several types of UPS systems that you should write about. The one you outlined is called a double conversion unit, which is always processing the power to give a clean regulated sine wave output. These are the least efficient and most expensive though. Double conversion is always taking the AC input, making DC, and using a PWM inverter to make regulated AC again for the output. Double conversion efficiencies are typically around 88-90% efficient, so this can impact you total system efficiency and operational costs. A cheaper UPS is the standby type, which allows the raw utility power to go straight to the load with some light duty surge clamping in between. When the input power voltage goes out of bounds, there is a switch over that is usually around 4-8msec which is faster than the PSU hold up time of 20msec. Since normal operation is straight pass through, the usual efficiency is close to 100% (minus the UPS internal power needs and charging). Note though that some UPS systems are crap and can use upwards to 100W just being plugged in.

I did not follow your discussion on the alarm buzzer indicating overcharge, which should never happen in any UPS. Most modern UPS system implement a battery test to make sure that the battery capacity and internal resistance is able to hold up the load. If the battery fails, they set off the buzzer. In almost all UPS systems, a buzzer alarm is critical - something is wrong. Some UPS systems also monitor the ground feed continuity and will alarm if the input feed ground starts to float making the UPS and the load unsafe to touch.

The UPS output waveforms are not all sine wave. Often the double conversion types are sine wave, adding to their cost. The standby UPS systems are usually step wave which is also called quasi-sine which is marketing term for step wave (to confuse the buyer). Most PC loads and monitors work fine with step wave (and are even more efficient on step wave!), although some PFC PSUs have problems. Magnetic loads can have real heartburn with step wave (motors, transformers) due to high losses and non-sinusoid voltage waveform effects.

Ferroresonant transformers are good voltage regulators, but the way they work is very lossy. A good ferro will only run around 90% efficiency. If your load is attached to a ferro, you are adding another power loss in your system. In my opinion, you are better off spend a few more dollars and getting a UPS (which there are ferro types still out there also).

There is no mention of oversizing your PSU also. Many HTPC and SOHO/home server needs are on 24/7 so power usage and efficiency are paramount to the cost of use / ownership. If you install an oversized PSU, you are taking a efficiency hit (for most brands) that increases your energy usage. The 80 Plus standards do not test below 20% load, so the efficiency of most PSU designs drop off quickly below 20% load. I have seen several that are below 50% with 10% loading. A good analogy on oversizing that I have used before is thinking about car engines. You cannot get a V8 car engine to run as efficiently as a 4 cylinder due to the physics (more friction/mass, etc.). That same effect occurs in a PSU. Larger magnetics, power devices, and other overhead lowers the efficiency at low power. proper sizing can save a good bit of money. Just don't get it too small, especially thinking about system start up (HDD spin up, fans, CPU local PSUs ramping up, etc.).

You comment on thermal shock is great, but there are many other factors to consider in reliability. Spinning down any HDD and fan loads reduces bearing wear for those mechanical parts. But keeping the main motherboard PCB powered and some operation continuing also helps with reliability. The minor amount of heat that is generated helps keep the PCB dry (PCB material is hydroscopic!), which one major part of the high voltage area in a PSU failing after a long storage (like right after purchase) causing a DOA. And as others pointed out in the comments, allowing the system to go into a sleep state will also cause a cool down thermal shock. The biggest problem with thermal shock is that it break solder joints and helps break bond wires/connections in ICs. It also speeds up electrolytic cap leaking and shortens the life. Does anyone remember the motherboard cap failure from a few years ago?

The absolute largest cause of computer failures is caused by ESD damage. The data from companies that keep statistics on this unanimously show this as a fact, but the PC enthusiast industry does not work to educate the end users of this well at all. In the electronics industry as a whole, ESD accounts for nearly 55-60% of all failures! This includes component suppliers, etc. So if you want a great topic for a future article, tackle ESD. It is real and it is very costly when ignored. Ever had a PC part that was DOA, i.e., that just "did not work at all" when powered up the first time and would not work at all? Good chance it was ESD.

Thanks for the article.
 

george21546

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Buy a power meter kill-o-watt comes to mind. Cost 15-20 and will tell you amps, watts, power factor and cycles per second. Best of all it will measure watts over time so you can check how much your system is using in each of it's states. I like to oversize power supplies by 25% unless upgrades are planned.
 

chris maple

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The low ends of the ranges shown are too high. Discrete video cards are available that use less than 10 watts, same for hard drives. Motherboards rarely exceed 25 watts.
My system has an Intel Core I7-870, discrete video card, 2x2G RAM, 2 1Tbyte hard drives, an SSD and a DVD burner. It usually runs at 70 watts and has never exceeded 200 watts driven hard.
 

hardcore_gamer

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[citation][nom]palladin9479[/nom]Holy cow. Thanks for that Asus PSU link. I now know what's causing my system instability.AMD Phenom II x4 980BE OC'd4 x 4GB DDR3-1600 memory2x NVidia GTX-580 SLI'd4x SATA ......[/citation]

You have a serious bottleneck there bro ;). Time to upgrade the CPU.
 

g-unit1111

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[citation][nom]palladin9479[/nom]Holy cow. Thanks for that Asus PSU link. I now know what's causing my system instability.AMD Phenom II x4 980BE OC'd4 x 4GB DDR3-1600 memory2x NVidia GTX-580 SLI'd4x SATA HDD's1x SATA DVDRW7x FANs (Water cooled system)Comes to 1150W recommended. I have a Corsair HX-1000 1000W PSU.[/citation]

Yeah... that floored me as well, mine is 900 minimum.

1 x AMD Phenom II X6 1055T OC'd
2 x Geforce GTX 550TI
4 x 4GB DDR3
1 x SSD
2 x HD
2 x DVD-RW
5 x CPU fans (double heat sink)

I know now what's causing most of my heat issues is that I'm running an underpowered PSU (Corsair 750). I will definitely make this my next upgrade.

And that thing about putting systems to sleep, I'll do that more often.
 

palladin9479

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Remember that ASUS link is calculating the approximate maximum power draw possible on your system. Basically with everything going full blast which doesn't happen too often.

PSU's in general start to get stressed once their over 80% of their rated output. Prolonged stress can cause components to wear out much earlier then before. This is why a PSU may be fine for awhile but then start to have random issues six months or more after installation. I just didn't think I was burning that much juice, but now it seems I am.
 

A Bad Day

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Just a question, is it worth watercooling a PSU? I know it would boost efficiency and allow it to put out higher watt than specified, but is it worth it?
 

palladin9479

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Umm what ... watercooling a PSU would be a very ~bad~ thing.

Unless your an engineer specializing in those things, do not under any circumstances allow water near a PSU, especially in a high powered system that would need WC to begin with. Your home insurance company will thank you.
 

nukemaster

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[citation][nom]g-unit1111[/nom]Yeah... that floored me as well, mine is 900 minimum. 1 x AMD Phenom II X6 1055T OC'd2 x Geforce GTX 550TI4 x 4GB DDR31 x SSD2 x HD2 x DVD-RW 5 x CPU fans (double heat sink)I know now what's causing most of my heat issues is that I'm running an underpowered PSU (Corsair 750). I will definitely make this my next upgrade.And that thing about putting systems to sleep, I'll do that more often.[/citation]
I would not guess you need that much. Your video cards together will have a hard time pulling 300 watts(and spend most gaming time in the 250 range). That leaves you with plenty of power for the system.

Corsair makes(ok, has made for them) very good power supplies.

This while informative, may have some inaccuracies.

@ A Bad Day.
The issue would be to water cool the transformer(its not built with the kind of surface you can mount a block on easy) it self(that thing can be pushes real hard with the right cooling). And leaks SUCK

@ All.
I know that I have trouble pulling much over 300(in fact have not managed it) watts on my system(single 5870 + 2600K @ 4.4 + 4 sticks of ram + 2 hard drives + 1 ssd + 4 120mm fans).
 

nukemaster

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Why would and SSD fail from sleep, it is no worse then turning off the computer.

Hibernate will push more write cycles, but general sleep does not(it just uses ram).
 
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