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Discussion Starter #1
Hello guys,

I bought (actually switched) for a Thermaltake 5,25" VGA power supply because I can't take any PSU anymore in my case (and no bigger ones then I already have...).

It spec's say:

* +12V1 rail and +12V2 rail
* 250W (300W peak)
* 21A (25A peak)

My question is, can I just combine them ?
My plan was to buy 2 female PEG connectors (normally on graphic cards) and stick both cables coming from the PSU to one female PEG connector. Then I solder/make some wires at each female connector, and let them come together in one normal male PEG connector, and plug this in my graphic card.
Would this work ?

Link to the PSU: http://www.thermaltakeusa.com/produc...0099/w0099.asp
 

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Quote:


Originally Posted by BETA911
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Hello guys,

I bought (actually switched) for a Thermaltake 5,25" VGA power supply because I can't take any PSU anymore in my case (and no bigger ones then I already have...).

It spec's say:

* +12V1 rail and +12V2 rail
* 250W (300W peak)
* 21A (25A peak)

My question is, can I just combine them ?
My plan was to buy 2 female PEG connectors (normally on graphic cards) and stick both cables coming from the PSU to one female PEG connector. Then I solder/make some wires at each female connector, and let them come together in one normal male PEG connector, and plug this in my graphic card.
Would this work ?

Link to the PSU: http://www.thermaltakeusa.com/produc...0099/w0099.asp

At the risk of sounding overly rude: why would you do that?
 

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Discussion Starter #3
I want the full potential off the PSU (so 250W and 21A) for one card...
Now it only uses 50% I think...
 

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You realise that electricity is drawn and not pushed? (in this application, anyways) As in, you GFX card will only draw what it needs from the PSU.
 

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Which graphics card do you intend on powering with this PSU? And with only 21A, I seriously doubt that it's enough.
 

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Discussion Starter #6
I know, but lets say, it splits his power in half.
So we got total 250W and 21A.

Split it, and you got +12V1 with 10,5A and 125W.
now I have a HD5770 hanging on it, wich consumes 9A under load. But what if I clock it to 1000/1400 speed, then it will consume much much more... So that's why I want to combine all the power, so when the card needs it, it can drawn it
.

EDIT:

My first situation was a OCZ 700W PSU for my i7 on 4.2Ghz 24/7 (but 4.5Ghz with benching) and my 2 cards. Calculating this, gave me 648W under load.
So, that's why I want to hook up one card to this 250W PSU (wich I have done already) but I want that the PSU can "give" all the power to this card when he needs it.
 

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Quote:


Originally Posted by BETA911
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I know, but lets say, it splits his power in half.
So we got total 250W and 21A.

Split it, and you got +12V1 with 10,5A and 125W.
now I have a HD5770 hanging on it, wich consumes 9A under load. But what if I clock it to 1000/1400 speed, then it will consume much much more... So that's why I want to combine all the power, so when the card needs it, it can drawn it
.

But it's usually far better to keep things simple and just have a single, normal PSU that can handle the entire system as it is.
 

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Discussion Starter #8
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Originally Posted by TwoCables
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But it's usually far better to keep things simple and just have a single, normal PSU that can handle the entire system as it is.

That I understand, but this was the cheapest (read: 0 $) solution.
Plus I don't have so much room for a long PSU (like a 850-1000W piece).

In that way, I must buy a 850W modulair PSU, and will cost me about 70-80$ above the selling price I can ask for my old PSU...
 

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Quote:


Originally Posted by BETA911
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That I understand, but this was the cheapest (read: 0 euro) solution.
Plus I don't have so much room for a long PSU (like a 850-1000W piece).

Fortunately, a PSU like that isn't necessary for the 5770 crossfired in this system. Hell, all that's needed is a high-quality 750W PSU.
 

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Yes, you can combine the rails.

Yes, you can use adapters to split the lines. The engineers who designed this were idiots. 6-pin PCIe is rated for only 75w so this PSU can only pull out 150w as is. They should have added a third PCIe wire. (Making one of the plugs 6+2 was another option but this unit came out before 8-pin PCIe plugs.)
 

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Discussion Starter #11
Quote:


Originally Posted by TwoCables
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Fortunately, a PSU like that isn't necessary for the 5770 crossfired in this system. Hell, all that's needed is a high-quality 750W PSU.

Even when pushin a i7 on 4.5Ghz (running about 366W) and lets say 2 HD5770's on 1000/1400Mhz for a good lets say 350W ?
 

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Originally Posted by DuckieHo
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Yes, you can combine the rails.

Yes, you can use adapters to split the lines. The engineers who designed this were idiots. 6-pin PCIe is rated for only 75w so this PSU can only pull out 150w as is.

Yeah, but the beauty of this is that most people don't know this which means it's easy money for them.
 

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Quote:


Originally Posted by BETA911
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Even when pushin a i7 on 4.5Ghz (running about 366W) and lets say 2 HD5770's on 1000/1400Mhz for a good lets say 350W ?

I believe so, yeah.
 

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Discussion Starter #14
Hmmm, don't want to trust on it really. I want some headroom...

Quote:


Originally Posted by DuckieHo
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Yes, you can combine the rails.

Yes, you can use adapters to split the lines. The engineers who designed this were idiots. 6-pin PCIe is rated for only 75w so this PSU can only pull out 150w as is. They should have added a third PCIe wire. (Making one of the plugs 6+2 was another option but this unit came out before 8-pin PCIe plugs.)

There you have a point. But my intension is not to split them, but combine them...
So you say, I just can combine them to one connector ?
 

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You guys do know that a HD5770 takes less than 100W, yeah? Close to 90W, if I remember right, and about 170W when CrossFired together.

An i7 clocked at the speed would be lucky to consume 200W, and the rest of your system ~50W.
 

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Quote:


Originally Posted by BETA911
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Hmmm, don't want to trust on it really. I want some headroom...

There you have a point. But my intension is not to split them, but combine them...
So you say, I just can combine them to one connector ?

I emailed Thermaltake about the rail distribution or max load a few years ago and never got a response. You may not have to combine anything if the OCP is high enough.
 

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Discussion Starter #17
Well, lets not forget the subject here.
I just want to know if I can combine them without any problem...

I don't want a HD5770 chip jumping around, or condensators inside the PSU flying around my ears...
 

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Originally Posted by meticadpa
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You guys do know that a HD5770 takes less than 100W, yeah? Close to 90W, if I remember right, and about 170W when CrossFired together.

An i7 clocked at the speed would be lucky to consume 200W, and the rest of your system ~50W.

Exactly. Most people on here would be absolutely shocked at how many watts their rigs actually draw at full gaming load. Mine draws less than half the capacity of my PSU.
 

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Discussion Starter #19
But, the main reason for this problem here is, that I have hooked up a PSU that has 250W, split in half, so 125W for a card that consumes 90W then, but when I overclock it, it will consume much more, so I want to hook this PSU up, that it can give the full 250W when the GPU needs it. Nothing more, nothing less...

So, can I combine them ?
 

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Quote:


Originally Posted by BETA911
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But, the main reason for this problem here is, that I have hooked up a PSU that has 250W, split in half, so 125W for a card that consumes 90W then, but when I overclock it, it will consume much more, so I want to hook this PSU up, that it can give the full 250W when the GPU needs it. Nothing more, nothing less...

So, can I combine them ?

You could use the Thermaltake power supply for the cards, yeah.

And there's no way the HD5770 comes close to 125W. Ever. The HD5870 takes <150W at stock in ALL applications.
 
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