Power supply size

J

Jon Boy

New Member
Is it bad to get a power supply bigger than your system needs? or is it ok. For example I bought a 750 Watt PSU for the computer listed bellow (new one). I know its too much but can it be harmful? This is what it says on its side.

DC -------------- 750W
AC Input ---------200-240VAC 60 hz
------------------11A
+3.3V ------------42A
+5V ------------- 6A
+12V ------------ 24A
+5V ------------- 0.5A
-12V ------------ 0.8A
+5VSB------------2A
+3.3V&+5VMAX -- 380 Watt

I have no idea what it meant just thought it might be usefull for well telling me what I want to know (maybe)
 
No there's no way it can be harmful. The powersupply will only output the amount of power your system needs. On the other hand, if the PSU is not powerful enough, potential problems can occur.
 
No offense.

That is the freakin worst power supply I have ever seen!!!!!!!!!

24 Amps???


That aint gonna power that Q6600 for an milisecond.
 
The wattage is fine, but the amperage is very low. It should power a Q6600 fine, but not if you plan to use a high end video card.

But to answer your question, a power supply will only use what it needs. If anything a beefier PSU will be better because it wont have to run at a higher load all the time.
 
HAHAHA so it pretty much sucks then. So you think I should cut my losses and see if there is a return policy?

The PSU is the only component I rushed into as I assumed they were well ... all very similar i.e. The higher the Wattage the better they were.
 
Wattage is important but you have to check where the power is going. 42A on 3.3V is a bit much. The 12V line is the most used one.
 
What PSU is it?

There's no way those numbers can be accurate (the +12V is possible, although ridiculously low for a 750W PSU, but the 5V rail can't be correct). Are you certain it doesn't have multiple +12V rails?
 
If the 12v rail is the 24 pin connector thing. Yes I only have one. And its a "Kimpro 750Watt ATX Sqitching Power Supply". Im not supprised its a piece of crap though only paid like £36 including postage in order to keep costs down and it looks like its gonna cost me money. The seller put this in the advertisment so I assumed it was good.
Seller said:
Brand New- Powerful 750W High End & Excellent Quality ATX Power Supply

120mm Large Transparent Bearing Fan, SLi Ready, Stylish appearance With 12 Months Warranty

VAT Already INC Above price

Provide PCI-Express 6 Pin Connector

( Good to working on the High End GFX Graphic Card)



Design for AMD Series, Dual Core Series, Pentium Series & High End Graphics cards
Click to expand...
 
This is a picture of a sticker on the rear of the PSU. Only thing I can think of if it is ok, they have the columns wrongly alligned? So the +12V is acually 60 and so on that would explain why the +5v is so high and the +12v so low?

Or do all the columns match up to what they should be?

 
Nope - the power on the +5V rail plus the power on the 3.3V rail should be more than the total power on the 5V and 3.3V rails, if the columns were reversed that would no longer be the case. Looks like you just got a poor PSU, looks like a reworking of a much older design. Any chance of returning it?
 
Well if I could would cost me some money, going to wait until they leave me some positive feadback before I ask. Otherwise they will leave me negative although there in the wrong for saying it does stuff which it cant.
 
Ok we have come to the conclusion my PSU is about as useful as a steam engine in powering my computer effectively. So suggestions on a NEW PSU?

I know I dont need a 750Watt PSU, what size should I get while runnign system bellow? I may add a second GPU some time when they come down to like £100.

Price is an issue I don't really want to spend more than £50 including postage.

Could someone suggest one with a decent +12v rail this time lol as I don't trust myself.

Thanks

Jon

EDIT: Any good?---> http://www.dabs.com/productview.asp...&SearchKey=All&SearchMode=All&NavigationKey=0
------------------->http://www.ebuyer.com/UK/product/124926
------------------->http://www.ebuyer.com/UK/product/132061
 
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Of those, the OCZ would be my pick. Still not something I'd recommend for SLI'd 8800s, but then again there's nothing at that price that I would. Fine for a single card though.
 
Guess I will get that then, and on that guide you wrote atleast I get one of the two things, the amperage is high enough on +12v rail is a total of 64A and only 52A is needed.

Just a question how do you use all these "Rails?" Is there like 4 leads instead of one if so where would I plug them into?
 
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Total amperage on the +12V rails is no more than 48A (you can't just add the individual rails together).

Each rail powers particular power connectors. In the case of the OCZ, +12V1 powers the first 4 pins on the ATX12V connector, +12V2 powers the other 4 pins and one of the PCI-E connectors, +12V4 powers the other PCI-E connector and +12V3 powers everything else.

You don't need to worry about the rail distribution when plugging things in.
 
Jon Boy said:
Well if I could would cost me some money, going to wait until they leave me some positive feadback before I ask. Otherwise they will leave me negative although there in the wrong for saying it does stuff which it cant.
Click to expand...

Ebay I supposed? Remember that wattage isn't everything.
 
Jon Boy said:
Ohh now im confused I thought it said on the 101 to look and combine the power on all the rails lol.
Click to expand...
yeah, I really need to fix that up - it's a little misleading (with a lot of older dual rail designs it was approximately true, but it's certainly not the case with triple and quad rail designs). For future reference, the total wattage available on the +12V rails is usually stated - dividing this number by 12 will give you the total amperage on the +12V rails.
 
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