"How many watts do I need"? Check Here!

[mariushm]

@Lilit

 

No. If the manufacturer is honest, the wattage of the PSU is the maximum amount of power (in watts) it can give to all the components inside your computer, through various output voltages.  Some devices use only 12v, other devices use 5v , others use 3.3v ... in total, the power supply is designed to give up to that much power (in watts) in a safe, controlled way.

For brief periods of time, or if the ambient temperature is much lower than normal temperatures, the power supply may be able to provide more than the advertised value.

 

The power supply produces that power with some efficiency, so if the power supply "sends" 100 watts to the components in your computer, the power supply actually takes more than that from your mains plug, from your house electricity sockets.

So for example if you know the power supply is 85% when it produces and sends 200 watts to components, then that means those 200 watts represent 85% of the total power the power supply took from the mains plug. 

So you have the basic formula :

 

200 watts  ..... 85%

? watts .... 100 %

 

Therefore,  the power supply took  ? = 100 x 200 / 85  = 235 watts from the wall.

 

Always keep in mind that if an honest power supply is advertised as 500 watts, then it should be able to give 500 watts to components, BUT it will actually consume more than 500 watts from the wall, and that difference is basically HEAT which must be pushed out using fans or natural air convection (in the case of fanless power supplies).

 

 

Your video card DOES NOT require 500 watts. The manufacturers of video cards have no way of knowing how honest the power supply is, which manufacturer makes it, and how much power the power supply can provide on 12v, which is the actual voltage used by the video card.

 

For example, let's say a user wants to install a GTX 1060 which consumes up to 125w.

 

User may have a 450 watts power supply which can provide 250 watts on 12v and 100w on 3.3v and 100w on 5v, so in total 450w. The video card only uses 12v so such power supply would not be able to power the processor AND the video card AND computer fans AND maybe a mechanical drive AND maybe some parts of the motherboard, all from those 250 watts of power on 12v.

 

Or, user may have a more modern 450w power supply, which produces all its advertised power on 12v, and from that it uses DC-DC converters to produce 5v and 3.3v, only as needed... so there's 100w reserved strictly for 5v, and there's no 100w reserved exclusively for 3.3v - now if the computer needs only 50 watts on 3.3v and 5v, there's still 400 watts left on 12v, which is enough to power all the components that want 12v, including a video card that needs up to 125w.

 

The video card manufacturer also doesn't know if the power supply is a shitty chinese no-name brand which has a fake label or says on the label "up to 500w for 50 ms, but 350w on average" - buyer sees only 500w because that's with big letters on the label.

 

So the video card manufacturers simply don't want the stress or returns and want to reduce the risk of video cards being damaged by low quality power supplies and simply say that a higher wattage power supply is required for the video card.  So for example, even though a video card may only use up to 125 watts (in the case of GTX 1060 for example), they may still say a 500w power supply is required.

 

You can easily determine how much power a video card is allowed to use by simply looking at connectors it has.  Remember: that's MAXIMUM it's allowed to use, not that it will use that much.

* The video card can take UP TO 75w from the pci-e slot.

* If the video card has a 6 pin pci-e connector, then it can take UP TO 75w from that connector

* if the video card has a 8 pin pci-e connector, then it can take UP TO 150w through that connector

 

So if the video card has a single pci-e 8 pin connector, then it will only ever be allowed to consume up to 75w (from pci-e slot) + 150w (from 8pin connector)  = 225 watts

 

Some video cards have 8pin connectors even though they don't strictly need it. Some designs don't take any power from the slot but take all the power from the power connector... or some use 8 pin connector even though a 6 pin may be enough, for overclocking or to make the card seem more powerful ("oh dude, it needs a 8 pin connector, it must be fast")  or maybe the video card manufacturer simply preferred to buy 100k 8pin connectors instead of two different connector types to save some money by buying in volume.

 

 

 

 

 

[mariushm]

10 minutes ago, Lilit said:

Thank you for the reply

 

@mariushm
Specs of the EVGA 1070ti SC Black Edition 

Requirements 

Minimum of a 500W Power Supply 

TDP: 217W (Never implied the 500W was the TDP) 
https://www.evga.com/products/product.aspx?pn=08G-P4-5671-KR

 

That is the equation I posted, you just removed the % and multiplied by 100. 

200 / .85 to 2000 / 85 

Thank you for the information

The card has a single 8pin power connector so at most it's allowed to take up to 75w+150w = 225w from the computer. 

TDP is short for thermal design power, it doesn't mean the video card uses that much power, just that the heatsink and fans are chosen in such a way to handle that much heat. On average, a GTX 1070 TI will use up to 175 watts, but that specific model is factory overclocked so it may use a bit more power. If  the user plays with the card further and overclocks it more, then it may get close to 217 watts or even more for brief periods of time.

 

As I explained, if the other components in the computer don't use a lot of power, then such a video card could run even on a 360w power supply, if the power supply is good. 

 

For example, here's this Antec Earthwatts 380w psu which can give up to 336w on 12v : https://www.newegg.com/Product/Product.aspx?Item=N82E16817371033&ignorebbr=1

 

If you use that card with a Ryzen 3 that uses around 40-50w and some ram and a ssd (another 25w for mb+ssd+ram), you'll still be way below 250-270w total power consumption.

 

EVGA is just covering their asses with the 500w minimum requirement. But this being said, there's often no point going with less than 5-600w because you don't save much money.  Just buy smart, like maybe buy a 500w gold efficiency psu instead of buying a bronze efficiency 600w psu.

 

[Stefan Payne]

1 hour ago, Lilit said:

@Stefan Payne

I'm learning as I go here as this is my first ever build, so bear with me. 

No Problem

I really like it, when you don't understand something you ask questions and we can help you.

Not knowing isn't a bad thing, as long as you are willing to learn and asking question.

Not knowing and not asking questions is a bad thing though.

 

1 hour ago, Lilit said:

The wattage of a PSU is the max amount it can output*. The efficiency of a PSU is the amount of wattage actually provided to components divided by the amount drawn from the energy source. 
 

Efficiency = System Wattage Use / Drawn Wattage 

A good PSU specifies the output capacity.

So a 550W PSU can deliver 550W to the components with a voltage/Amperage distribution according to the Label wich is the Specification of the PSU.

 

Efficiency the ratio of wattage drawn from the Wall to what is used.

And a Power Loss occurs (wich is technicly wrong because Energy can't be lost, just converted. In this case it means power is converted to an unusable form, wich is mostly heat).

 

1 hour ago, Lilit said:

Using my build, the total system wattage is 299W while the GPU requires at least 500W to operate meaning the PSU must be at least 500W 

No

That is a recommendation from the manufacturer in a very simplistic matter - wich makes it wrong because it is too simplistic.

The Problem is that there are many different grades of quality and power distribution. Today not so much but in the olden days it was more of an issue...

 

The point is that the only rail that matters today is the +12V Rail. And there were 500-550W PSU that can have for example 336W non +12V (Old Topower P4 based ones from various manufacturers anno 2003 to 5)

In the more recent years its more like ~400W for example Cooler Master Silent Pro 500W.

And there are also PSU that have 100% of its rated wattage on +12V.

 

The point I'm trying to make is that you can't write something like "400W on +12V" because nobody would understand, so you take a look at what is available, pick the worst ones and use those for your Watt Rating.

 

And that's why its overrated by 100, maybe 200W: because the manufacturers have to simplify it so much.

 

 

1 hour ago, Lilit said:

With my GPU having a 500W PSU minimum requirement, the 550W would indeed suffice depending on quality, but it appears to be the minimum to just keep things going, no?

No, its just a legally binding recommendation from the GPU manufacturer based on ancient data and rather shitty PSU.

If a GPU states 550W minimum but you know the TDP and have a rather lower Power CPU, you can get away with a good quality 400W PSU.

On the other hand, getting a shitty quality 600W can cause you more problems again because of the low quality, dependant voltages and other things.

 

 

Buttom Line: Go for the best unit you can get and don't care too much about wattage.

400-550W is more than enough for a modern single GPU/CPU System with no to moderate OC.

 

1 hour ago, Lilit said:

And I did read the OP, but some of the recommended PSU are below some GPU requirements. 

Its not a requirement, its a recommendation

A very simplified version that is based on PSU data from 10 Years ago (or more)...

 

1 hour ago, Lilit said:

Example results from other calculators. 
CoolerMaster PSU Calculator: 650W recommendation. And as you mention, inflates individual part wattage
EVGA Part Meter: 550W, 600W and 650W recommendations depending on PSU efficiency 

NewEgg PSU Calculater: 400W recommendation without taking into account GPU requirement 

Yes, but a 450W Bitfenix Formula is better than a 600W EVGA W1 in every point.

But the PSU manufacturer assumes that you have a worse quality unit, not a good one and "calculates" their wattage recommendation accordingly.

 

The "Power Meter" you cited, are just adders that take values out of a Database, add them and throw them at you. 

But the Wattage is more on a theoretical worst case level that can never happen in Real life and that is the Probem.

Under normal gaming loads we are talking about something like 250-300W with your System.

[The Old Camper]

Hello all,

This is my first post

 

I'm considering to upgrade my system's PSU, in order to upgrade the GPU (currently it runs perfectly fine with the 460W stock PSU and GTX 1060...)

 

Current configuration : Dell XPS 8900 with stock PSU (460W)

Motherboard - Dell XPS 8900 (chipset: LGA 1151 / Z170)

Processor - Intel Core i7-6700 

CPU Cooler - stock

GPU - GTX 1060 FE -> to be upgraded to GTX 1080, GTX 1080 Ti or future nVidia high-end GPU (no overclocking)

Memory - DDR4, 2x8 16GB, 2133MHz

SSD1 - M2 Hynix, 256GB

SSD2 - PCIe - M2 adapter with Samsung 950 Pro, 512GB

HDD1 - Seagate 2TB, 7200rpm

HDD2 - Seagate 1TB, 7200rpm

DVD/CDRW Combo Drive

Case fan x3

 

Special PSU requirements: compact dimensions 140 mm (W) x 150 mm (L) x 86 mm (H)

 

I've been considering Seasonic's PRIME Ultra 650 W Platinum (SSR-650PD2) for months, but I can't get hold of it. However, both the 550W and 750W versions are now available. I would prefer to aim for the best efficiency in order to keep power consumption & heat to a minimum.

 

According to http://www.coolermaster.com/power-supply-calculator/ the load wattage would be 448W (GTX 1080) or 520W (GTX 1080 Ti), however their recommended PSUs are either 700W or 750W!!

 

Do you think the Seasonic PRIME Ultra 550 W Platinum would be enough? If so, is it worth the upgrade from the stock 460W?

 

Thank you

[Stefan Payne]

4 minutes ago, The Old Camper said:

Current configuration : Dell XPS 8900 with stock PSU (460W)

 

Do you think the Seasonic PRIME Ultra 550 W Platinum would be enough? If so, is it worth the upgrade from the stock 460W?

 

Thank you

1st:
Check if it is really ATX and can be used.

 

2nd: You do NOT really need a higher Wattage PSU, especially not 650W. That is something that should only be used on high end desktop systems with highest end cards and a bit of OC. Otherwise its pretty hard to get close to 600W...

 

[The Old Camper]

@Stefan Payne Thank you! Apparently other users of this case have successfully upgraded it with an ATX PSU so I will give it a shot...

[MxMayhem]

Obviously new to this forum. But looking to upgrade my power supply so I can put my old one in my wife's system. Currently using the cheapest one I could find at the time. But found a cooler mast MasterWatt 750 semi Modular at a good deal. Not sure how worth it that is. 

 

Ryzen 5 1600 (3.8ghz OC) 

RX 580 GIGABYTE (1500mhz OC) 

1 TOSHIBA Mechanical HD (7500 RPM)

1 Samsung 960 Evo m.2

1 Drevo sata m.2

1 Samsung SSD

Cooler Master ml240l aio

16gb crucial ballistix sport ddr4 2400mhz (4gb x4) 

Asrock ab350 pro4 motherboard 

3 140mm fans (1200 rpm) 

2 120mm fans on aio 

Nzxt sentry 3 fan controller. 

And rgb backplate on the gpu

An led strip in the case

And a bunch of USB 3.0 peripherals plug in among various other crap. 

 

Should I look for a 650 instead? 

Probably going to grab a Ryzen 7 and 1080ti on the future (and OC them) 

Any advice is welcome! 

[EsaT]

15 minutes ago, MxMayhem said:

But found a cooler mast MasterWatt 750 semi Modular at a good deal.

 

Probably going to grab a Ryzen 7 and 1080ti on the future (and OC them)

If you can afford luxury graphics card then you should afford modern efficiency and better performance PSU.

 

And unless going for overvolting to create electric room heater quality 650W PSU would be enough.

[awesomegamer919]

19 hours ago, MxMayhem said:

Obviously new to this forum. But looking to upgrade my power supply so I can put my old one in my wife's system. Currently using the cheapest one I could find at the time. But found a cooler mast MasterWatt 750 semi Modular at a good deal. Not sure how worth it that is. 

 

Ryzen 5 1600 (3.8ghz OC) 

RX 580 GIGABYTE (1500mhz OC) 

1 TOSHIBA Mechanical HD (7500 RPM)

1 Samsung 960 Evo m.2

1 Drevo sata m.2

1 Samsung SSD

Cooler Master ml240l aio

16gb crucial ballistix sport ddr4 2400mhz (4gb x4) 

Asrock ab350 pro4 motherboard 

3 140mm fans (1200 rpm) 

2 120mm fans on aio 

Nzxt sentry 3 fan controller. 

And rgb backplate on the gpu

An led strip in the case

And a bunch of USB 3.0 peripherals plug in among various other crap. 

 

Should I look for a 650 instead? 

Probably going to grab a Ryzen 7 and 1080ti on the future (and OC them) 

Any advice is welcome! 

A better quality but lower wattage PSU would be better, think Bitfenix Whisper M/BeQuiet Straight Power 11, if it needs to be even cheaper then Bitfenix Formula. If those brands are not available then the Corsair RMx is another good, though often pricey, option, finally there's the Cougar GX-F, it's performance is a little worse than others mentioned but not to any noticeable degree and it's very price competitive (at least in EU).

[awesomegamer919]

On 5/3/2018 at 7:51 AM, mariushm said:

User may have a 450 watts power supply which can provide 250 watts on 12v and 100w on 3.3v and 100w on 5v, so in total 450w. The video card only uses 12v so such power supply would not be able to power the processor AND the video card AND computer fans AND maybe a mechanical drive AND maybe some parts of the motherboard, all from those 250 watts of power on 12v.

 

Or, user may have a more modern 450w power supply, which produces all its advertised power on 12v, and from that it uses DC-DC converters to produce 5v and 3.3v, only as needed... so there's 100w reserved strictly for 5v, and there's no 100w reserved exclusively for 3.3v - now if the computer needs only 50 watts on 3.3v and 5v, there's still 400 watts left on 12v, which is enough to power all the components that want 12v, including a video card that needs up to 125w.

I don't think I've ever seen a 500w PSU that has <400w on the 12V and can output 500w (Unless it had an absolute shitload on the 5V and is some 20 years old).

[mariushm]

1 hour ago, awesomegamer919 said:

I don't think I've ever seen a 500w PSU that has <400w on the 12V and can output 500w (Unless it had an absolute shitload on the 5V and is some 20 years old).

True, but there's all kind of shit out there.

 

Here's an example, new power supply that they sell as 485w but in reality it's more like 200w : https://www.newegg.com/Product/Product.aspx?Item=N82E16817339020&ignorebbr=1

 

 

 

or one not quite as fake, logisys 575w :  https://www.newegg.com/Product/Product.aspx?Item=N82E16817170017&ignorebbr=1

 

It's not 575w ... it's 450w max on all rails, 575w maybe burst max, for a few ms....  max 250w on 3.3v + 5v , so that leaves 450w-250w = 200w on 12v ... it's say this would be a 360w psu if they wanted to label it properly.

[OrionFOTL]

1 minute ago, mariushm said:

Here's an example, new power supply that they sell as 485w but in reality it's more like 200w : https://www.newegg.com/Product/Product.aspx?Item=N82E16817339020&ignorebbr=1

 

I swear I have nothing to do with that. 

[MrNiceOne]

Hello, so im building my first PC ever.. And im stuck between 550w and 650w (PSU will be from #1 list)

Can i even over clock little bit with 550w psu? Or maybe i should go 650w to be safe?

Main parts:

 

Cpu>Intel Core i7-8700K

GPU>GeForce GTX 1080 ( normal or maybe TI )

MoBo>Asrock Z370 Extreme4

Cooler> Be Quiet Dark Rock 4

Ram>2x8GB DDR4

SSD>240GB

HDD>2TB

[awesomegamer919]

21 hours ago, MrNiceOne said:

Hello, so im building my first PC ever.. And im stuck between 550w and 650w (PSU will be from #1 list)

Can i even over clock little bit with 550w psu? Or maybe i should go 650w to be safe?

Main parts:

 

Cpu>Intel Core i7-8700K

GPU>GeForce GTX 1080 ( normal or maybe TI )

MoBo>Asrock Z370 Extreme4

Cooler> Be Quiet Dark Rock 4

Ram>2x8GB DDR4

SSD>240GB

HDD>2TB

You could pull off a max OC on 450w, 550w for "muh safety/headroom/upgrade path/(insert excuse here)"...

[Ehsan77]

what power supply do i need for my pc :

 

ryzen 1600x

MSI B350 mortar

geil 16 g   2x 8g

MSI  GTX 1060 3g gaming x

128g ssd       1T hdd 7200

 

[Sakkura]

19 minutes ago, Ehsan77 said:

what power supply do i need for my pc :

 

ryzen 1600x

MSI B350 mortar

geil 16 g   2x 8g

MSI  GTX 1060 3g gaming x

128g ssd       1T hdd 7200

 

450W would be plenty. A Corsair CX450M would be a cheap option if you're in the US ($30 with a mail-in rebate right now). As for a high-quality option, the Corsair TX650M and Seasonic Focus Plus 450W would be great. The 650W is unnecessary but doesn't hurt anything, and it's actually a couple bucks cheaper (at least if you count the rebate).

[Stefan Payne]

59 minutes ago, Ehsan77 said:

what power supply do i need for my pc :

 

ryzen 1600x

MSI B350 mortar

geil 16 g   2x 8g

MSI  GTX 1060 3g gaming x

128g ssd       1T hdd 7200

 

if you don't have the 3GiG Card, don't get it. If you bought it: Condolences.

 

What to get depends on where you live, what's available.

 

If in Europe:
Bitfenix Formula, Whisper M, be quiet Straight Power 11 (450W or 550W).

[P3X979]

I recently upgraded from a Ryzen 1600 & 1050ti to a Ryzen 2700x and 1080ti.  The EVGA 1080ti came with a Free EVGA 650W G2 80+ Gold Power Supply.  I am currently using a 750W Rosewill 80+ Bronze PSU from a build I did in 2014.  My set up is as follows:

 

CPU: AMD Ryzen 7 2700x

GPU: EVGA GTX Geforce 1080 ti

Mobo:  MSI B350M Gaming Pro

RAM:  Corsair Vengeance 3200 MHz 2 x 16GB

SDD:  Western Digital Blue 250GB

HDD:  Western Digital Blue 1TB 7200RPM

PSU:  Rosewill ARC 750W 80 Plus Bronze

 

My question is would it be better to run with the new "Gold" 650W or keep using the four year old "Bronze" 750W?  I understand that EVGA G2 Series is a higher tier product than Rosewill ARC Series.  How many watts do I really need with this system?  I don't game, but will be using this computer for Data Science/Machine Learning projects, so GPU and CPU will see use.  I don't plan on overclocking the CPU or GPU. Thanks

[mariushm]

Your whole system will peak while gaming at around 350-400 watts,  so either power supply will barely reach or go over half its capacity.

In such scenario both power supplies would be at near their peak efficiencies (probably around 92% for the 650w gold and around 85% for the rosewill arc psu)

 

If you game a lot, let's say at least 4-6 hours a day, it would make some financial sense to switch to the gold efficiency psu, as you'd save maybe a handful of dollars at the end of the month on your electrical bill.  The 650w gold psu may also be slightly more silent compared to the bronze efficiency one (due to lower efficiency it will heat more so fan will spin faster to push air out) BUT the fact that it may be more silent won't really matter much because when your computer uses 2-300w forcing the psu to spin its fan, the video card will also spin its fans and the fans of the video cards will be much noisier than the psu.

If you don't care about power efficiency the old 750w psu should be perfectly fine still. It is a bit old if you say it's from 2014, but if it's not dusty and fan spins nicely then should be no issue.

 

So basically both power supplies are perfectly adequate but it would be a good idea to install the new 650w gold and sell your bronze one if you want.

 

If you're not gaming, the system will probably not go over 200w or so ( 1kWh for every 4-5h of use or around 0.15-0.3$  on your  bill) .... the 2700x alone will go up to around 140w if use at its maximum  (all cores used at peak frequency etc, like for example when encoding videos) and the video card when using OpenCL or Cuda to render stuff or do calculations on the video card will use some power but usually below what it would normally use for gaming (rarely cuda and opencl loads manage to load a video card as much as a video game)
 

[P3X979]

I appreciate the help.  I was using different Power Supply calculators and they were giving me different numbers:  from 430W to 595W.  I'm pretty sure they are all designed to sell you power supplies.  I figured I'd ask people with real world experience.  Thanks.

[Vuu]

I'm planning to upgrade to the RX 580 8GB, and am wondering if I will need a new PSU, since I'm using an old "600W" (the 12V rail delivers like 457W according to the panel) Raidmax and I don't want that thing turning into a fireworks show...

 

In that case, the configuration would be:

 

I7-4771

RX 580 8GB

16GB DDR3 RAM

and a bunch of shit with basically no consumption (SSD, 2x HDD, dvd-r drive)

 

I was at first thinking of SAMA Forza 750W but that might be overkill

[awesomegamer919]

Way overkill, a decent 550w would work fine and said FORZA series is good enough... 

[Stefan Payne]

4 hours ago, Vuu said:

I'm planning to upgrade to the RX 580 8GB, and am wondering if I will need a new PSU, since I'm using an old "600W" (the 12V rail delivers like 457W according to the panel) Raidmax and I don't want that thing turning into a fireworks show...

Yes, you need a new PSU as the old one is old, group regulated and not compatible with modern Hardware. Continue to use that will damage the new Hardware.

 

FOr that you don't need no 750W or even 600W, a good quality 400-450W PSU is more than sufficient.

 

Depending on where you live a be quiet Pure Power 10/400W is the bare minimum you should consider, though it would be best to go with either a Straight Power 11, Bitfenix Whisper M or if it should be a bit cheaper the Formula is a good option or the Cougar GX-F.

 

As said, the 450W are sufficient but you could also grab the 550W.

Ifthey are available for a good price that is.

[mariushm]

The RX 580 will consume less than 200w. The cpu and the rest of your system, probably less than 100w.

 

So overall, when you're gaming, I don't think your system will use more than around 250w (because neither the cpu and the video card will stay at 100% usage all the time)

 

So in theory that Raidmax would still be suitable, but in practice considering the age and the unknown quality of the components and especially the fan, it would be a good idea o replace the power supply.

 

I wouldn't suggest going for a sama 750w, especially if you can go for a 550w-650w gold efficiency from a better known brand (seasonic, corsair, evga gold series of psus, superflower on the higher end of their series etc)

SAMA isn't bad, but you can probably do better.

[awesomegamer919]

44 minutes ago, mariushm said:

The RX 580 will consume less than 200w. The cpu and the rest of your system, probably less than 100w.

You can get an RX580 to draw 200w+ pretty easily...

44 minutes ago, mariushm said:

So overall, when you're gaming, I don't think your system will use more than around 250w (because neither the cpu and the video card will stay at 100% usage all the time)

I'd disagree, OP could easily see up to 300-320w of power draw (from PSU secondary side)

44 minutes ago, mariushm said:

So in theory that Raidmax would still be suitable, but in practice considering the age and the unknown quality of the components and especially the fan, it would be a good idea o replace the power supply.

Raidmax = almost universally bad, their only good unit is a Titanium Andyson rebrand

44 minutes ago, mariushm said:

I wouldn't suggest going for a sama 750w, especially if you can go for a 550w-650w gold efficiency from a better known brand (seasonic, corsair, evga gold series of psus, superflower on the higher end of their series etc)

SAMA isn't bad, but you can probably do better.

Corsair and EVGA don't make their own PSUs (EVGA uses Superflower/FPS with a single gold Seasonic unit, Corsair uses Channel Well and Great Wall) and both have gold rated PSUs that are worse than the SAMA FORZA...