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PSU Question on New Build

Meekers

Meekers

Member
I have been saving old parts from several of my builds and reached the point where I had almost enough for a new build so I decided to pick up the missing parts and use the new build as an office computer.

So I am using an i7920 and an AMD 4870. The only new part I really needed was a PSU. I entered that and all the other components into a PSU calc and got 335 W. I decided on a Corsair CX430. I am not going to be doing any overclocking on this build so the PSU should be fine with these parts.

Unfortunately, I failed to account for the fact that it only had 1 6-pin PCIE power cord and the 4870 needs 2. I have never used a Molex-PCI converter, are there any concerns using them? Wondering if I should go that route or take the time to exchange the PSU.
 
If you can exchange the PSU at no cost, I would go for it. However, a CX 430 should be sufficient to run your setup without any problems.

If you want, you can check out the Corsair CXM 500 for only $35 after MIR and after promo code with free shipping on newegg.

I doubt you paid much less than that for your CX430.

Alternatively, you can stick with the PSU you have now and get a splitter that would turn your single 6 pin into two 6 pins or a molex to PCI-e adapter.

Note that the second link (molex adapter) ships from Asia which usually takes about 2 weeks from my experience.
 
If you don't overclock the card, and it's reference speed, 1 PCIe will be fine. Like the GTX 460 a little later, they made the 4850 and 4870 specs to 150W at stock speeds, but gave them 2 connectors, because most of them were good to speeds and voltages that would exceed 200W. if it's a factory-OC model, you might want to have that extra connector. An adapter from 12V will generally be fine, and you might still have that from when you bought the card in the first place.
 
So I ordered a molex adapter but tried to get the computer running with just 1 6pin connector. It is not posting at all when I power up, led indicator on the monitor never changes to indicate it is receiving anything.

The fans on the gpu are spinning, as are all the case fans and cpu heatsink. DVD drive opens so everything seems to be getting power. It has an SSD so cannot tell if that is active or not.

Should I just wait for the Molex adapter and try again or so I start trouble shooting other components.
 
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I think you will be fine once you hook up both power cables into it. If you don't see any debug LED codes or hear beeping, it's almost certain that the lack of power on the video card is causing the issue.
 
Typically, the cards will POST fine with no PCIe hookup. Not 100% on that for that series Radeon, though.
 
Cerb said:
Typically, the cards will POST fine with no PCIe hookup. Not 100% on that for that series Radeon, though.
Click to expand...

Not any card I've seen. They have a failsafe that will refuse to power up the card if it doesn't sense voltage on all the PCIe power pins. This is to prevent the card from burning out the PCIe slot by trying to draw 150W through it.
 
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OK, you got me. When they start doing that?
GTX 460 - nothing.
8800GS - to the desktop.
(I have nothing else around that uses extra connectors)
 
If its just an office PC then go on ebay and buy a used office-level gpu for $15. Radeon 4550 is a good one for that. Also, if you never load the GPU heavily, then it will never know the difference between 1 and 2 pciE power connectors. Just verify with an ohmmeter that the two headers connect to each other pin for pin.
 
Got the Molex adapter today, and did not post on first try. Ended up swapping ram to other set of sockets and it posted. It is running fine now though, thanks for the help.
 
Cerb said:
OK, you got me. When they start doing that?
GTX 460 - nothing.
8800GS - to the desktop.
(I have nothing else around that uses extra connectors)
Click to expand...

Sometime between the 8800GS and GTX 760 obviously. 😉 But seriously I think the GT200-based cards were the first on the Nvidia side.
 
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