How do I setup Dual PSU's for a high end system?

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hcforde

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Oct 29, 2006
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I am setting up a system with 2-5870 2GB Radeon's. I ordered a 750 Watt Corsair 750TX. Now I am wondering if it will be enough? The system will also have an i7-860, and an Asus P7P55 WS Supercomputer motherboard, with a Corsair H50.

Yes I have looked at the PSU calculators and some reviews and forum post concerning power requirements.........and the story is not clear. Since I got this unit from Newegg I do not really want to go through the hassle of sending it back and waiting if I can get around it.

So I remembered a guy at the OLD Compusa in Austin that connected 2 power supplies for this monster machine he built for a special customer. He showed me the connection, but since I had no use for it(at the time) I did not look that close but I know it can be done. This is just an electrical connection that turns the units on and off simultaneously nothing more.

I want to run my main System off of the main unit and the fans and all the rest off of the secondary unit.



ANY IDEAS OR EXPERIENCE???

Thanks
 
You don't need another PSU. A TX750 is perfectly fine for 2x 2GB 5870s. You have 5870s, not GTX 480s.

When I used to have a TX750 in my 5870 system, the entire system didn't even draw 350W @ the wall. I crossfired with a borrowed 5870 once and it was about 540W total for the system. At most, you'll be around 650W on an overclocked machine.

The idea of running fans on the other PSU is pretty silly. Most fans only draw 5 watts. If you have 5 fans, that's 25 watts. It won't make a difference.
 
ya but that 750tx is only good at 750 peak watts. You don't want to be running the psu at full power 24/7. It has an average power at 80% of 750.
 
Seer37 said:
ya but that 750tx is only good at 750 peak watts. .
Click to expand...

Wrong....that is a continuous rating...not peak

Not to mention he wouldn't be running the PSU even near its rated wattage 24/7....unless he his hot bunking with a bunch of buddies who like to run 2 games at a time at extreme resolutions....
 
its actually pretty simple...

by a power supply extension (24 pin) cost about $6

tap into the number 14 and 15 pins and extend them to the 14 and 15 on your other power supply...

that's the basics of what you are trying to do....

I doubt hat you will need to do this but hey its your computer...
 
another way to do it is to buy an 4 pin automotive relay, any amperage should do... connect the 12v positive and 12 volt negative (from your main power supply) to pins 86 and 85 on the relay... then attach pins 30 and 87 on the relay to pin 14 and 15 on slave power supply
 
Thanks all for your responses. I did pick up a P3 Kill-A-Watt unit so before I combine PSU's I will measure my usage to see if it is necessary. If it is necessary I would like to have an alternative way of supplying power to my system.

OK EricFX1984,

You have presented me with 2 very different solutions. The simple one was the one that I am sure I was looking at, at CompUsa.

SEEMINGLY SIMPLE SOLUTION
by a power supply extension (24 pin) cost about $6, tap into the number 14 and 15 pins and extend them to the 14 and 15 on your other power supply...

SEEMINGLY ELEGANT SOLUTION
another way to do it is to buy an 4 pin automotive relay, any amperage should do... connect the 12v positive and 12 volt negative (from your main power supply) to pins 86 and 85 on the relay... then attach pins 30 and 87 on the relay to pin 14 and 15 on slave power supply
Click to expand...

Now, what can you tell me about the more elegant solution. What are the advantages of it?

Thanks
 
hcforde said:
Now, what can you tell me about the more elegant solution. What are the advantages of it?

Thanks
Click to expand...

the biggest advantage it that you don't have to have a big adapter on display as you can simply hide the relay anywhere... I did this way way back in the day

basically this is the cleaner way to do it
 
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