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Psu calculator says 297 watts for whole pc but .. .. ..

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November 10, 2010 6:18:39 PM

hi guys,

please see this link :

http://www.coolermaster.outervision.com/PSUEngine

and tell me why ati says 5770 needs minimum of 450 watts??
i can use 300 watts for this pc

i3 540
p7h55-v
2gb ddr3
500 gb hd
5770 1 gb
a c 130 U Graphics card
November 10, 2010 6:25:23 PM

Just looking at your system specs i would say a 450Watt PSU would be what you want. I cant stress enough how much a decent PSU is worth in terms of ruling out possible power related issues.
It really comes down to the quality of the PSU. Corsair do a 400 Watt PSU that i wouldn't hesitate to put on that system but that would rule out any upgrading in the future.
I rated the PSU to the hardware on the very first PC i built but soon learnt to over spec the PSU to allow it to be taken forward to newer builds and to allow for hardware upgrades.

If you have a prefered website and budget i will gladly (along with others im sure) provide some recommendations.

Mactronix :) 
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November 10, 2010 6:27:23 PM

why shouldnt i can use 300 watts for this pc?
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a c 130 U Graphics card
November 10, 2010 6:46:09 PM

edenkhan said:
why shouldnt i can use 300 watts for this pc?


its just not a good idea to run a PC on the edge of what power it needs to run properly. You may decide to run it on a 300 Watt PSU anyway and have no issues and think "Ha what did they know" OR it could fail when asked to deliver more than its really capable of and fry your whole computer. Extreme and unlikely but possible.

When the makers sell a PSU its rated in Watts. Your Graphics card doesnt work in Watts its more concerned with how many Amps are on its +12V rail. Depending on the make model of PSU there may be 1-2 or more of these rails.
The real issue is here because, and there really is no way to sugar coat this some makers lie about the actual available Amperage. When i say lie i guess provide misleading information as to the Amperage available would be more legally correct.

With that in mind what is the make and model of your PSU and what does it say on the information plate as far as all the rails are concerned ?

Mactronix :) 
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a c 235 U Graphics card
November 10, 2010 6:46:14 PM

1. you don't want your PSU running at peak power constantly.
2. the quality range of PSU vary so ATI/nvidia must overstate their PSU requirements to cover themselves for the lowest quality ones.
3. a quality 400w PSU from enermax, seasonic, corsair, silverstone, antec will power your rig with no issues. OCZ also offers some budget models.
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a c 172 U Graphics card
November 10, 2010 7:10:15 PM

Never use psu calculators as the values they use for calculations are a matter of speculation. Go with a psu that is a sure thing when it comes to your needs and always buy a quality unit that has more than you need for safe measure.
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a b U Graphics card
November 10, 2010 7:40:16 PM

mactronix said:
its just not a good idea to run a PC on the edge of what power it needs to run properly.

His system could be run on a good quality 300 watt psu without much of a problem, other than most likely needing to use a molex to pcie adapter.
For the record, I did try to steer him towards a 400-450 watt unit in order to provide room for upgrades.
http://www.tomshardware.com/forum/293451-28-clear-confu...

PS ; He's currently got a Thermal Master 420 with 16 amps available on the 12v
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a c 130 U Graphics card
November 10, 2010 7:58:30 PM

delluser1 said:
His system could be run on a good quality 300 watt psu without much of a problem, other than most likely needing to use a molex to pcie adapter.
For the record, I did try to steer him towards a 400-450 watt unit in order to provide room for upgrades.
http://www.tomshardware.com/forum/293451-28-clear-confu...

PS ; He's currently got a Thermal Master 420 with 16 amps available on the 12v



That's the thing though isnt it, a good quality PSU sure but when you are recommending things to people you don't want to risk suggesting something that even has an outside chance of doing any harm to software.
People like yourself and I understand what to look for in the specs and can calculate for ourselves. I personally have run cards on PSU's that others have exclaimed total shock at, because they don't fully understand whats actually needed compared to what gets recommended.
As i said thats fine for us that know what they are doing but if someone asks a generic question like can i run this on a 300 Watt PSU then the answer from me will always be no.
I generally hold that if the card needs a single PCIE connector and the PSU has one then it should be fine. Even that gets shouled down sometimes.

Mactronix :) 
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November 10, 2010 8:08:43 PM

hi again dell user !!

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November 10, 2010 8:11:17 PM

mactronix said:
its just not a good idea to run a PC on the edge of what power it needs to run properly. You may decide to run it on a 300 Watt PSU anyway and have no issues and think "Ha what did they know" OR it could fail when asked to deliver more than its really capable of and fry your whole computer. Extreme and unlikely but possible.

When the makers sell a PSU its rated in Watts. Your Graphics card doesnt work in Watts its more concerned with how many Amps are on its +12V rail. Depending on the make model of PSU there may be 1-2 or more of these rails.
The real issue is here because, and there really is no way to sugar coat this some makers lie about the actual available Amperage. When i say lie i guess provide misleading information as to the Amperage available would be more legally correct.

With that in mind what is the make and model of your PSU and what does it say on the information plate as far as all the rails are concerned ?

Mactronix :) 



thanks brother

but the main problem is that as i asked before in some other thread that 5770 needs atleast 30 amps. so, should i buy more than 30 amps psu as other components also need some amps. or 12v/18 amps psu will be ok? why?
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a c 130 U Graphics card
November 10, 2010 8:53:16 PM

I will try to RE- explain what Dell user tried to explain on the other thread although i wont be telling you anything that you have not been told before i don't think.

You need a certain amount on your +12v rail/s Yours i believe is a 16 Amp rail ? When you add up the full usage of your system including peripherals such as HDDs your CPU and your GPU, you are very close to fully loaded as far as what the PSU can actually supply. This puts you at risk of overloading the PSU and as i said maybe hurting some of the other hardware in your system.
You want to be looking at a PSU that has a minimum of 28 Amps as far as im concerned. Your card isnt actually going to be using that much power but its needed to ensure that the rail the GPU is feed from has enough juice in it to power the card properly.
A lot of PSU's these days have dual rails. You don't actually just add these up for the correct Amperage of the PSU you need to know the Wattage supplied to the +12v rails then divide that by 12 to give you the correct Amperage of the PSU. This is because the rails are rated to the maximum they can supply but they cant always both provide the maximum together, a quality PSU can and does.
Your card actually needs about 9 Amps itself and as i said to Dell user if its got a PCIE connector then it should run the card.
As long as you understand the risks involved then you can try it but i really would advise you to get a quality PSU first.

Mactronix :) 
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a c 171 U Graphics card
November 10, 2010 11:33:41 PM

1. it is a bad idea to run a PSU near its max output
2. not all PSU's produce their rated output continuously, most cheap brands are PEAK value and may vary at different temperatures and may only supply a limited amount to the most important 12v rail
3. ATI reccommends 450w as this should account for overrated cheap PSU's and will allow the card to run reliably without straining the PSU.

If you dont stick to what the manufacturer reccommends dont whine about it when things dont work and your computer blows up.
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a c 358 U Graphics card
November 11, 2010 12:08:07 AM

edenkhan said:
why shouldnt i can use 300 watts for this pc?


You can, but it may be an expensive lesson the learn that it is not smart to do so...

If you are gonna use a calculator to figure out your power consumption, then it's always good to divide that wattage by 0.8. That's 80% of the PSU's maximum power and do not confuse that with peak power 'cause peak power is for very short measure of time.

Why 80%? Well that's a personal thing... Before the standardization of the 80PLUS certification, most good quality PSUs were near or at their maximum efficiency (based on reviews). That's not to saying they were 80% or more efficient though, just the maximum which could have been as low as 65% efficient. It also gives you a bit of room for upgrades as well. 90% is basically where you should max out, anything above in my opinion, will be detrimental to the life of both your PSU and your PC.
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a b U Graphics card
November 11, 2010 12:11:47 AM

edenkhan said:
thanks brother

but the main problem is that as i asked before in some other thread that 5770 needs atleast 30 amps. so, should i buy more than 30 amps psu as other components also need some amps. or 12v/18 amps psu will be ok? why?



The 5770 is a 108W board so will usually only use a max of 108 watts under load (though if you Overclock the card you might go slightly above that it is spec'd to use 108w max. So that would mean that the card will use 108/12 = 9 amps (since amps x voltage = watts !) -- so the card itself will only use around 9 amps as was mentioned (the 30 Amp recommendation is for the entire system not for the card !) -- the problem with using a 3oow psu is that that is the maximum the psu is designed to output total on all the various voltages and that may or may not be distributed in a way that allows enough of the power to be on the +12v which is what most modern systems use the most ( several years ago systems used much less +12v power and instead used more +5v or +3v power and some PSUs still distribute much more to those voltages and less to the +12v rails so just giving the overall wattage a PSU can provide does not tell the whole story -- you need to consider how that power is distributed for use and how the system you are using it in requires it.

So in order to be on the safe side the video card manufacturer will overstate the need in order to ensure that by following the recommendation you will be able to run the card without problems -- so you might be able to run a 5770 on a smaller PSU IF the voltages are properly distributed and the PSU is rated correctly and not overstated (many low end units are tested in a refrigerated room because they can output more power in a colder room but trying to run them in a normal environment will cut the output significantly and the PSU may not be able to reach its rated output level) but to be safe follow the manufacturers recommendations
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a b U Graphics card
November 11, 2010 2:09:22 AM

edenkhan said:
why shouldnt i can use 300 watts for this pc?


Power Supplies are rated 2 ways.

Continuous Output
Peak Output (Surge output)

In most cases, the PSU manufacturer doesn't list which rating is being used. If you purchase a PSU with a 300watt Peak Output Rating.....you will lose money, a PSU and whatever else it takes out. If you purchase a PSU with a 300watt Continuous Output, you might be safe hitting the power button to turn it on.....but why risk damaging an entire computer to save a few bucks?
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November 11, 2010 5:47:29 AM

can any one tell me how much amps xigmatec 500 watts psu got? some of my friends are using it with the same pc as mine even they dont know about their psu's amperage. but its running fine

by the way Thanks to all :) 
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November 11, 2010 6:04:26 AM

I guess the simple answer is test it using a killawatt meter. My recommendation would be to run p95 and furmark at the same time. That would give you the worst cast scenario power draw. Most PS run at @80% of the wall voltageso if the killawatt says you are drawing over 375 watts then you are over driving you PS. I would recommend that you upgrade you PS to at least 450 watts. You can find them on sale for @35-45 dollars all the time. It is worth having a quality ps that is not being overdriven. An overdriven PS can cause all kinds of random crashes, fry your mobo, or fry itself. Buy an Antec 450w or higher when they go on sale. It is worth the small investment.
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November 11, 2010 6:15:22 AM

is cooler master 460 watts a good choice for the budget?? members on pakgamers.com hurted me on cooler master they only say " buy xigmatec " whats yours opinion about it?
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a c 130 U Graphics card
November 11, 2010 7:18:18 AM

The cooler master 460 is a pretty good match for what you want i have one in a PC in mt daughters room. It was speced for a 3850 which power wise is more or less the same as a 5770.

Mactronix :) 
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a c 235 U Graphics card
November 11, 2010 11:27:31 AM

the xigmatek 500w has 37a on its 12v rail

the CM 460 is a cheap unit and runs like a cheap PSU. you could do better and you could do worse. I would personally take the xigmatek 400w over the CM 460, it peaks well over its stated power and is more efficient.

extreme power 460 review

Even though this power supply can’t deliver its labeled power, it isn’t a bad product for its price tag and targeted audience. Its real power is close to its labeled power (430 W) and its efficiency isn’t bad for a low-end product. Plus it has all its protections up and running, a thing sometimes hard to find on cheap power supplies.



http://www.hardwaresecrets.com/article/Cooler-Master-eX...

elite power 460 review

Cooler Master Elite Power 460 W is simply an Elite Power 400 W with a new label. The two units are absolutely the same (the only component that was upgraded was the rectifying bride, but this change didn’t make any difference in performance). This is simply unbelievable. We wouldn’t be surprised to see this kind of thing still happening in China, but here in the United States? C’mon…


http://www.hardwaresecrets.com/article/Cooler-Master-El...
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a b U Graphics card
November 11, 2010 12:17:04 PM

edenkhan said:
can any one tell me how much amps xigmatec 500 watts psu got? some of my friends are using it with the same pc as mine even they dont know about their psu's amperage. but its running fine

by the way Thanks to all :) 


IF it is the Xigmatec NRP-pc502 (product #CPH-0500U-X02) then it has 2 +12v rails rated at 20Amps each with a combined output rating of 37Amps (444W) - so it is a very good PSU and is also 80+ bronze certified so should be fine in your system.

If it is the Xigmatec NRP-VC503 (product #CPH-0500Q-X01) then it has 2 +12V rails rated 16A and 15A (they do not list the combined output but list the MAX for each rail as 192 and 180W respectively) so still OK for your usage but not nearly as high quality as the NRP-PC502 model would be (since it is their low end value line of product !)

And this just goes to the thing that everyone has been trying to explain to you -- as you can see even from the same manufacturer you have 2 seperate 500w PSUs that vary greatly in the actual specs even though both are sold as 500w PSUs !! One of which is very high quality and could be used in a system that was pushing the 500w usage while the other is lower quality and would not be a good fit in a system that was pushing that limit ( though it is still adequate for your usage since you are well below 500w (BUT THIS is why the Video card manufacturer must recommend a 450w minimum for the 5770 since they do not know which model you as a user might buy -- the high quality or entry level PSU !!!!)
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a b U Graphics card
November 11, 2010 1:02:02 PM

JDFan said:
IF it is the Xigmatec NRP-pc502 (product #CPH-0500U-X02) then it has 2 +12v rails rated at 20Amps each with a combined output rating of 37Amps (444W) - so it is a very good PSU and is also 80+ bronze certified so should be fine in your system.

7 out of 10 at jonnyguru, wouldn't call it very good, but certainly better than what he currently has.
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a b U Graphics card
November 11, 2010 1:30:10 PM

delluser1 said:
7 out of 10 at jonnyguru, wouldn't call it very good, but certainly better than what he currently has.


True -- I quess I was looking at it in context with the other listed version (when comparing to their entry level alternative then it is much better than the alternative but if looking at it compared to other manufacturers then you would be correct !)
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