How many Watts do I need?

piemasterp · Jul 1, 2011

Ok, I am going to upgrade my video card this fall at the latest, and I was wondering how many watts my new PSU would need. I currently have a Thermaltake PurePower 430, the crappy one that only produces 300 watts and spits sparks out the back (not really).

My Build includes
Phenom II x4 840
4 GB of DDR3 ram
Gigabyte 870A-UD3 Motherboard
2 SATA 250 gb HDDs
1 320 GB usb drive
Front panel card reader
1 80mm fan
1 120mm fan
stock AMD heatsink

and occasionally an old Saitek joystick

The graphics card I am planning on upgrading to is the Radeon HD 5770 (Thinking either Asus or Saphire, whichever has a low enough sale)

Ive asked around on other forums (non tech ones, but with computer sections), irc chat rooms, and asked friends. Ive gotten everything from 300 watt up to 900 watt. One PSU calculator told me 600 watt, but the most common im hearing from people is the 400-500 range. How many watts do I need, and what is the cheapest quality PSU in that range that I can get.

browsingtheworld · Jul 1, 2011

Your system will draw ~250-300W max load. Antec sells some nice/cheap 300-400W PSUs.

PSU calculators are for dummies. Just add the TDP of your components together, primarily the video card and CPU. The CPU is ~100W and so is the video card. The rest of your system should be 50-70 watts.

king smp · Jul 2, 2011

sorry btw
look at this techpowerup guide
TDP doesnt take into account load wattage
http://www.techpowerup.com/reviews/AMD/Phenom_II_X4_840/10.html
the 840 will use more than 95w TDP
TDP is not your max load
http://en.wikipedia.org/wiki/Thermal_design_power

this is 5770 specs
http://www.amd.com/us/products/desktop/graphics/ati-radeon-hd-5000/hd-5770/Pages/ati-radeon-hd-5770-overview.aspx#3

also why would you recommend a PSU of 300-400
when total max load is easily around 300w?

You dont want your PSU running over %80 of its rating EVER if possible'
DONT push a PSU that hard
A tech would know that
to recommend a 300w - 400w PSU for the combination of the 840
and the HD 5770 is dangerous advice

I agree Antec is a good choice
this would be the minimal PSU for this system
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371034&cm_re=antec_430w-_-17-371-034-_-Product

that is a 430w CONTINOUS Wattage PSU
and really that is on the lower end
Doesnt leave room for alot of components
like dual DVDrws,multiple hard drives and higer powered cards

this would be a better choice and a great deal right now
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371031&cm_re=antec_power_supply-_-17-371-031-_-Product

would leave the OP headroom for future upgrades
and is priced nice right now

Silvune · Jul 2, 2011

http://www.guru3d.com/article/radeon-hd-5770-review-test/11 - 321W at the wall, furmark
http://www.bit-tech.net/hardware/graphics/2009/10/13/amd-ati-radeon-hd-5770-review/10 - 213W at the wall, 3DMark06 Canyon Flight Test
http://www.anandtech.com/show/2856/13 - 256W, not stated, I assume that it is furmark
http://www.tomshardware.com/reviews/radeon-hd-5770,2446-15.html - 207W at the wall, furmark

The Guru3D review has the highest number for power consumption, at 321W, the next highest is 256W @ Anandtech. The first two reviews use i7-965s, Anandtech uses a i7-920 and TH uses an i5-750.

So, 321W at the wall. If the PSU was 90% efficient then only 32W would have been wasted as heat, 64W if the PSU was 80% efficient. So 290W actual system power draw. So I agree that a 300W PSU is looking a bit low. But I have really gone for the worst case numbers.
With the other system with a 95W TDP CPU; the i5-750 in the TH review showed 207W at the wall. Obviously the i5-750 uses less power than the X4 840, altho I would think the X4 840 would be closer in power consumption terms to the i5-750 than the i7-965. This would be under 200W for actual system power draw.

You could definitely safely power a build with a 5770 on a high quality 300W PSU, but it is probably a justifiable decision to think that it is on the low side. 400W, no problems whatsoever.

Can't really disagree with the recommendations for the Antec Neo Ecos.

900W is definitely overkill, unless you have serious upgrade plans, such as running two GTX 580s.

oby20 · Jul 2, 2011

500w would be enough but ofcourse you wont go for the minimum, get a 600w psu to be much safer and also for future upgrades if you needed upgrades for some parts then the 600w will still be good for you. try to get a branded 600w psu, from FSP, Corsair, Enermax, Antec. these are good psu makers.
but i suggest you go for FSP everest 600w. affordable yet good quality psu.

browsingtheworld · Jul 2, 2011

king smp :

As demonstrated by multiple websites thanks to Silvune in a worst case scenario for an HD 5770 with an overpowered system, much more powerful than his, the maximum power draw is 300W. His system would draw not even 250W at maximum load in a worst case scenario. I feel perfectly comfortable recommending a 350W Antec PSU, their cheapest:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371003&Tpk=antec%20350w

Can you please not make up numbers, it's very bad feedback.

king smp · Jul 2, 2011

I stated and also sourced that 300w as YOU said would be max
so what are you talking about?
PLEASE READ THE OTHER POSTS BEFORE YOU TALK!

so why would you want a 350w PSU when max draw would be 300w
that is dumb
when he wants to add other components or higher powered card in
the future he would not have the headroom to do it

a good 450w would be the least I would use

you dont want your PSU ever getting close to %100 of the max wattage
rating
Since it will max at 300w as I SAID and you SAID and the other poster said
then a 350w is too low
Basic tech knowledge

browsingtheworld · Jul 2, 2011

king smp :

You linked the separate TDPs of the CPU and GPU without any of the other components neccessary to run a computer like the HDD, motherboard and RAM and got the wrong number at the end. I said 250-300W as a worst case scenario if somehow he had 2 optical drives burning discs with an extreme overclock, I feel perfectly comfortable recommending a modern 300W PSU for his computer.

Again, the draw would be maybe 250W max TDP during gaming even with an extreme system (as extreme as that one can get).

I gave a PSU range. A 400W PSU would give him all the headroom he needs unless he gets a video card that's not going to be fully utilized by his CPU anyways.

What do they test the 100% continuous load efficiency for 80+ certification for then? Please give me some evidence that running a system at 95% load on a quality PSU is bad.

350>300. Basic numbers. :lol:

This SeaSonic 350W would not be stressed at all in his system under almost any circumstance.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151077&cm_re=350w_seasonic-_-17-151-077-_-Product

I suggest you actually read and understand something about PSUs before making recommendations:
http://www.overclock.net/power-supplies/715889-psu-articles.html#post9110838

king smp · Jul 2, 2011

Wow thanks for the source
Your very link to overclock.net
proved my point

to quote
So you should get a PSU the size so that your peak draw is around 50% of the PSU's load, right? No, not in most cases. Think: 90% of the time your computer will be idling, usually drawing only 75W-200W, depending on the computer. So you want your computer to be very efficient in that power range. Generally you want your idle power draw to fall into ~30%-40% of the PSU's rated wattage, and your peak power draw to fall into ~70%-80% of the PSU's rated wattage.

that is from YOUR link
why dont you read your own info?
this is YOUR link
http://www.overclock.net/power-supplies/711542-efficiency.html

READ IT
not just look at the pretty pictures

By the way do you make a living working on a computer?
I do
what do you do for a living?

king smp · Jul 2, 2011

BTW
%80 of 350w is 280w

his system can peak over that
that means NO headroom
would you really want to run a PSU like YOU recommended at 350w
that could go over %80 of it rated peak?

good way to kill the PSU and the computer

PLEASE STOP MAKING BAD RECOMMENDATIONS ON TOMS
YOUR GOING TO GET SOMEBODYS SYSTEM RUINED!

Leave the real work to the Big Boys
Go back home Son

king smp · Jul 2, 2011

And read this
http://www.tomshardware.com/forum/277636-28-read-first

that is a sticky on the rules of the forum
you already have other members wanting you BANNED
follow the rules or leave

browsingtheworld · Jul 2, 2011

king smp :

You do realize he's recommending buying a lower wattage PSU right?
http://www.overclock.net/power-supplies/872013-50-load-myth.html
The article is titled The 50% Myth and explains how you shouldn't buy an excessive PSU.

For his system that might draw 250W max under a really extreme circumstances (overclocked burning DVDs while gaming). That's 90% of the 276 over 12V for the Antec 350 (and the total system power isn't all over the 12V either). It would fall within the recommended 70-80% range for the Seasonic even if it only drew power over the 12V. Again that's an extreme case. The 350W PSU is plenty (either one).

What do you do for a living? :pt1cable:

king smp :

Again, with an overpowered i7 system the HD 5770 used about 250W max load during games.

That's also now how you calculate how much wattage the PSU can supply. You just look at what the PSU can give you over 12V which covers most of the system. The 80% efficiency means off the wall. For example when your PSU is outputting 320W it's really drawing 400W from the wall. The SeaSonic I linked you can provide 324W over 12V (and not everything is powered by the 12V), not 260W as your math suggests.

You do realize I recommended a SeaSonic right?

You really should read these articles/posts, your PSU knowledge is clearly lacking.

king smp :

First thing I noticed was:

Don't...

Post in ALL CAPS or use excessive punctuation!!!

:lol:

Maybe you should reread that post yourself

king smp · Jul 2, 2011

I will post this again
since you have no reading comprehension whatsoever

to quote
So you should get a PSU the size so that your peak draw is around 50% of the PSU's load, right? No, not in most cases. Think: 90% of the time your computer will be idling, usually drawing only 75W-200W, depending on the computer. So you want your computer to be very efficient in that power range. Generally you want your idle power draw to fall into ~30%-40% of the PSU's rated wattage, and your peak power draw to fall into ~70%-80% of the PSU's rated wattage.

that is from YOUR link
why dont you read your own info?
this is YOUR link
http://www.overclock.net/power-sup [...] iency.html

READ IT
not just look at the pretty pictures

you see and follow carefully here
you shouldnt run a PSU more than %80 of it rated wattage as overclock.net stated
so %80 of 350w is 280w
basic math .80 x 350 = 280w

so that system will have no "headroom"

what cant you understand about that

I write in all caps whent talking to you
since you cant seem to comprehend

answer my question

Do you make a living working on and repairing computers?
Have you had any formal training in a school?

Answer those questions

browsingtheworld · Jul 2, 2011

king smp :

No, that's not what he said. There's nobody with any semblance of knowledge that will say you shouldn't run your PSU over 80% if it's a decent PSU. He has just said ideally you want to have your system's peak power draw to fit within 70-80%. He didn't say it was bad to run your PSU at 90% or even 95%.

Again, peak power consumption maybe 250W or as you suggest 280W under an extreme scenario. That's still within the ideal power draw range for a 350W PSU.

Yes if the system consumed 280W there wouldn't be much headroom with a 350W PSU but that's because the only way he would ever consume 280W is if he was pushing everything to the max anyways in which case he's not going to be able to do more in terms of overclocking and won't draw any more power.

No to your two questions but at the very least I know to calculate (more like look on the label) to see how much power a PSU can really output instead just making up some numbers using the efficiency rating which has nothing to do with how much power a PSU can output.

king smp · Jul 2, 2011

Listen I am not looking to get into a flame war with you
Everybody is welcome here
But alot of members are complaining about you and your advice
It is not just me
I looked up and checked your threads

why would you suggest a PSU that barely covers what he needs now
a PSU should last a few builds
at the very least the OP should get a decent 430w like the seasonic
or the Antec 380w
but in the future I am sure he is going to get more powerful cards than
the Hd 5770 or add other components
so why wouldnt you recommend a PSU that has room to grow when they
dont cost much more

right now he could get this
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371031&cm_re=antec_power_supply-_-17-371-031-_-Product

normally a $100
$69 on sale
after rebate $50 with free shipping
cant complain about an Antec
supply
and if the OP wants to drop in a more powerful card
he could
and plus it would run more efficiently

Some of the stuff you have posted makes sense
and I make mistakes
but when the mistakes are pointed out

I admit to them
I dont insult the person who pointed it out
I do my best to correct them
I take responsibility for my mistakes

Sure that 350w would work
but why limit yourself?

that Seasonic 350w you linked is $42 with $8 shipping
so the antec 620w is $50 with free shipping

wouldnt you buy the Antec 620w for the same money as the Seasonic 350w?

I never meant to get into a fight with you

I like the Xigmatek 92mm you recommended on that cooling system thread
but I have personal experience with the Zalman and I checked with a respected
member (malmental) to double check the recommendation

so what was your problem with that?

I didnt look to start a fight with you

browsingtheworld · Jul 2, 2011

king smp :

I said 300-400W, it's a range so i don't understand why you're offended. If you think an Antec 380W is fine then you shouldn't really say anything about my recommendations. Yes 300W would be the low range but that's exactly what it is, a range.

Sure he could get that 620W PSU, but how much further do you expect him to push that system, especially considering he doesn't have a real Phenom (2MB L2). The next time he upgrades his system might be a few years in which case there will be better PSUs since they always get better and he'll probably have to get a whole new system to see a dramatic increase in performance. It's not a bad suggestion but the 300-400W would do and you shouldn't suggest otherwise. I agree that's a great deal but it's probably not going to be used, costs more, is actually less efficient (than the SeaSonic). When he does upgrade maybe 1-2 years down the line is he still going to want to use that 620W ATX 2.2 PSU that's not new anymore? Just something to consider.

As for that XK cooler thing it wasn't a huge deal either way but I linked a benchmark where it showed the XK was both cooler and quieter than the Zalman. Plus it cost less. It's not a bad cooler, the other one was just better.

Never trying to fight, just bored (guard shack

) and trying to clear some things up.

king smp · Jul 2, 2011

Okay I can agree with some of that
but
it doesnt cost more
after rebate it is $50 with free shipping
the seasonic you listed is also $42 + 8 shipping
of course rebates can be a pain in the neck
but Antec is usually pretty good about their rebates

here is quote from Newegg
The NEO ECO 620C power supply combines the most desired features in PC power supplies with unprecedented efficiency in design. The Antec NEO ECO 620C power supply power supply features 80 PLUS certification, saving energy and your money. It also generates less heat, and enhances cooling with a super-silent 120mm fan. The Active PFC circuitry further reduces impact on the power infrastructure resulting in cooler, quieter, and more environmentally friendly power.

The Antec NEO ECO 620C power supply’s Universal Input capability together with ATX12V and EPS12V compliance enables you to use it in a variety of situations, and almost everywhere, without worrying about input voltages. Dedicated power circuitry, industrial grade protection circuitry, and Active PFC deliver safe, reliable output.

The presence of one Main connector (20 + 4 pin), one 12V rail (4+4-pin), six Molex, six SATA, one Floppy, and two PCI-E (one 6-pin and one 6+2-pin) connectors are more than enough for all your components. The single +12V output circuits provide maximum stable power for the CPU independently of the other peripherals.

as you can see it is ATX V 2.3 not 2.2

that PSU could easily last a few builds

do you disagree that you should buy a PSU that should last more than one build?

i have been taught to buy your PSU and case with the idea that it will
be good for 2-3 builds minimum

and running a PSU to0 close to rated max is not a good idea

I pointed out the Antec 380w as a minimum choice
really wouldnt go less than the Seasonic 430w
remember also that PSUs degrade over time
(capacitor aging)
so the 350w is fine for now
but after a year or two it is really pushing it
and would have to be upgraded for next build

doesnt even costs more to get a 550-650 on a good deal

Trust me I deal with OEM factory pieces of crap that give you just the
amount of PSU you need with no headroom for expansion

You dont want that

Emperus · Jul 2, 2011

I would love to "enter the den" here but I believe there is a similar confusion going on in a similar thread. Now why don't we let OP give us a budget figure (for the PSU) and then we can find him a good unit which is not only enough for his current build but also sustains through future builds/upgrades.

@browsing : There are certain components on which any investment is worthwhile. PSU is one of them. A good and slightly higher wattage PSU can carry you through many builds. So it is mostly a future cost saving investment. I can easily merge the capacitor aging or reduction in total output power or efficiency reduction terms here but that will only boil up this thread and make it more confusing. Let's keep it simple for the time being.

king smp · Jul 2, 2011

Good point Emperus
the OP stated cheapest quality 400-500w range
in which case I would pick this one
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371023&cm_re=antec_power_supply-_-17-371-023-_-Product
about the best deal in cheaper 400-500watt range

king smp · Jul 2, 2011

also to be fair
this Xigmatek looks nice for price
http://www.newegg.com/Product/Product.aspx?Item=N82E16817815007&cm_re=xigmatek_power_supply-_-17-815-007-_-Product

though I would want to double check JohnnyGuru for reviews on both

Emperus · Jul 2, 2011

I saw that Xigmatech unit mentioned before on a similar thread. Looks good. But the spec page is a bit confusing. With 20A mentioned on each 12V rail, this unit is supposedly a 500W unit. Is that a typo or suggests something else! Sorry, too lazy to google.

Also, someone suggested an Antec BP350 somewhere. @OP : Stay away from it. Please go through the specification page for more info. Even the very basic Corsair CX 430 V2 will be loads better compared to it.

king smp · Jul 3, 2011

Emperus :

Emperus you just nailed Best Answer in my opinion

this is the Corsair CX 430 you are referring to?
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139026

The OP wanted the best quality cheapest 400-500watt PSU
and that one is 24.99 after mail in with free shipping
plus JohnnyGuru recommended

@ OP - my recommendation is the Corsair CX 430 as Emperus said
and I would vote Emperus Best Answer if this was my thread

browsingtheworld · Jul 3, 2011

king smp :

Correct about the ATX 2.3. I should mention it's only 80+ and power supplies only get more efficient.

The PSU can last a few builds but you're assuming he's going to take it out of his current system and scrap it instead of keeping it and he doesn't want to get a new PSU later one when they will undoubtedly be even higher quality.

The SeaSonic 350W PSU would be more than sufficient. Capacitor aging doesn't really happen with modern PSUs which use solid caps (it does but you'll only see a difference after like 10 years and I hope he doesn't keep his PSU 10 years).

Not everyone likes mail in rebates. I think everyone prefers a cheaper upfront value.

Again, read what I said about headroom and how the only way he even gets close to using 250-280W is an extreme overclock in which case he's not doing much more anyways.

It's not a bad choice to get the more powerful PSU but there's nothing wrong with a lower powered one either.

Emperus :

The XK unit is actually the same as it's 500W and 600W big brother's according to Tom's From the reviews and user ratings it's a really high quality PSU. At the very least it's specified to provide 384W.

The CX is better but it costs more. I didn't say otherwise. I'm still certain the BP350 can power his system unless he has an extreme overclock and optical devices.

king smp :

The CX430 has 336 watts over 12V, only 12W more than the SeaSonic I recommended. I just wanted to point this out because you were talking about headroom. It's a good choice, especially for the price but doesn't give you any more useable wattage than the SS350W. Either way they are both good brands that will be provide more than enough power.

king smp · Jul 3, 2011

piemasterp :

Be that as it may
The OP asked for the "cheapest quality PSU" in the 400-500w range
So Browsingtheworld and myself were both WRONG
BTW picked a good 350w
and I picked a good 620w
so neither one of us picked what the OP wanted

now Emperus picked the Corsair CX 430 v2
which is very inexpensive and probably the cheapest in that range for a good quality PSU

So I hope the OP likes his choice
And so far Emperus has Best Answer in this thread

Do you disagree Browsing?

piemasterp · Jul 5, 2011

Wow. You guys are confusing the noob... Budget is $60 after rebate, but I would prefer lower. I have my eye on the Antec EA-430D. Is there a non-eco version that is cheaper, but still the same build quality?

[EDIT] That Corsair Emperus suggested is right up next to the antec, and its cheaper too. Has anyone had any problems with Either of them?

How many Watts do I need?

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