# Finding the right PSU...

## meulie

Hi all,

I'm in the process of figuring out what PSU I need for a system I am about to put together, probably with the following specs:

Antec mini P180. Intel Q6600 quad core CPU, 4x2GB DDR3 RAM, 4x SATA drive, onboard graphics.

Perhaps 1 or 2 USB devices hooked up every now and then)

I am trying to use a calculator to determine my requirements, but the outcome seems too low to be correct: < 275W! Can it really be that little? Or am I missing something here...?

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## Akkara

There's a thread asking advice about building a PC with a bit of a sub-thread regarding power supplies.  I'll paraphrase one of my posts from that thread as is seems relevant here:

The rule-of-thumb is to use a power supply rated at twice what your typical power draw will be, since that is its most efficient point.  (See, for example, this graph.)  That power supply would be a good choice if you expect an average draw around 260 W.

Not counting the graphics card, most computers draw around 100-150 watts.   It is the high-end graphics card that can draw immense amounts of power - often as much or more than the whole rest of the computer.  Since you are using the onboard graphics, which tend to not be power hungry, the numbers you are being quoted seems to make sense.

Be sure to look for "Active Power Factor Correction" when choosing a power supply.  I find that power supplies with it tend to be more efficient in general as well as stand up to load better when pushed toward their maximum.  It is also easier on the power lines (less power loss in the line compared to the spiky current draw of the old rectifier-and-filter-capacitor design.)

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## techie705

Thats about what I get from there also, but I'm sure you have heard it said plenty of times BUT I will say it again.

Don't skimp on your PSU it can cause hard to track problems to just about taking out your whole system if it goes bad.Last edited by techie705 on Thu Jul 31, 2008 2:15 pm; edited 1 time in total

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## Monkeh

 *techie705 wrote:*   

> Thats about what I get from there also, but I'm sure you have heard it said plenty of times BUT I will say it again.
> 
> Don't skimp on your PSU it can cause hard to track problems to just about taking out your whole system if it goes bad.
> 
> Here is what I have just for reference http://www.newegg.com/Product/Product.aspx?Item=N82E16817182150.

 

Nice one. Those are some of the worst PSUs about, fyi.

This is made by the same people: http://www.hardocp.com/article.html?art=MTM5NywxMSwsaGVudGh1c2lhc3Q=

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## techie705

[quote="Monkeh"] *techie705 wrote:*   

> Thats about what I get from there also, but I'm sure you have heard it said plenty of times BUT I will say it again.
> 
> Don't skimp on your PSU it can cause hard to track problems to just about taking out your whole system if it goes bad.
> 
> Nice one. Those are some of the worst PSUs about, fyi.
> ...

 

I took the link from my post cause I don't want someone else's rig to blow up and have it be my fault.

I'll just sit back and wait for mine to go cause I have the worst PSU on earth.  :Evil or Very Mad: Last edited by techie705 on Fri Aug 01, 2008 1:05 am; edited 1 time in total

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## zyko

 *Quote:*   

> I am trying to use a calculator to determine my requirements, but the outcome seems too low to be correct: < 275W! Can it really be that little? Or am I missing something here...?

 

275W is a very prudent estimate. I'd guess that you'll never even break 175W under full load.

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## Monkeh

For a machine like that, I'd buy a 350-400W PSU. Don't forget you have to factor in startup surge (HDDs all spinning up at once, etc). Something like a 380W Seasonic S12II.

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## meulie

 *Monkeh wrote:*   

> For a machine like that, I'd buy a 350-400W PSU. Don't forget you have to factor in startup surge (HDDs all spinning up at once, etc). Something like a 380W Seasonic S12II.

 

Exactly the unit I came across as well during my research! Although... I'd prefer one with modular cables, so I don't have a lot of crud hanging in my case... Any good SeaSonic with modular cables?

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## Monkeh

 *meulie wrote:*   

>  *Monkeh wrote:*   For a machine like that, I'd buy a 350-400W PSU. Don't forget you have to factor in startup surge (HDDs all spinning up at once, etc). Something like a 380W Seasonic S12II. 
> 
> Exactly the unit I came across as well during my research! Although... I'd prefer one with modular cables, so I don't have a lot of crud hanging in my case... Any good SeaSonic with modular cables?

 

M12II range. Same supply, modular cabling. Or look at Corsair (if they do lower end PSUs), as theirs are made by Seasonic.

There's also Enermax, the Modu82+ series has a 425W model.

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## pdr

Personally I always buy Seasonic. I currently have a 550 W (workstation) and 600 W (winblows gaming rig) - both modular. Sometime in the future I'll upgrade my E6750 in the workstation to a Q6600 and have no doubts the 550 will still be fine. Have a low-end graphics card in there (ATI x700) since I don't like my southbridge trying to drive my 1900x1200 monitor, and am very sure the 550 will still be fine at load.

Also Seasonics (haven't checked in a while tho) were a favorite at silentpcreview.com

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## Monkeh

The current SPCR pick is the Enermax Modu82+. It's quieter and more efficient than anything Seasonic has released thus far.

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## meulie

Their 425W model looks quite promising!  :Smile: 

Too bad I can't seem to find anyone in Norway who sells it...   :Sad: 

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