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HX520: with 975XBX2 4 Pin

TX Kiwi

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I haven't built a PC in years (since Pentium was new thing!) and am just embarking on a build for a machine primarily focused on video editing. Parts are arriving and I'm just starting to get my head around integration.


Re exisiting thread: http://www.houseofhelp.com/forums/showthread.php?t=55472


I'm also using the Bad Axe 2 mobo. However, the requirements in my mobo guide are different to the text quoted by the original poster. My mobo manual reads:


"Use of the 1x4 power connector is required with ATX12V power supplies with 2x10 power connectors when using PCI express cards that can consume up to 75W."


Since the HX520 has a 24 pin main connector then this appears to make use of the 1x4 'Alternate Power Connector' on the mobo redundant?????


Note that I will be using a single Sapphire X1650 PRO PCI express graphic card and reviews note that it can consume over 100W.


Query 1 . Am I correct that the 1x4 power connection is not required because I'll be using the HX520's 24 pin connector to the mobo?


Query 2 - I might run the power to the 1x4 anyway, just for insurance. The advice on the original post was to use a standard modular molex connector from the PSU. However, to keep the number of cables down, is it feasible to use an adapter on the 4-pin +12V (2x2) connector [that is part of the HX520 main power loom] to convert it to a 1x4 molex?


Query 3 - I will be running 3 SATA HDD (one is a WD Raptor for OS) and they'll all be in Kingwin KF-813 removeable caddies (each with three 40mm fans). Additionally the case has three 120mm fans (all CoolerMaster). Does the HX520 have enough juice or should I have gone for the 620?



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The Intel manual is rather unclear about the extra 1x4 (molex) power connector on the motherboard. That connection is only needed if using a PCI card that draws more the 75W and does NOT have it's own power connection. So, if you video card has a seperate power connection on the card, the auxillary 4 pin molex conntion to the mobo isn't needed. If the card doesn't have it's own power connection, and you think it will draw more than 75W, then use the auxilary molex connector on the motherboard.
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Thanks Pisles, I'll check the Sapphire X1650 PRO power requirements when it turns up. However, the specs for it don't mention on-board power and pics of it don't show a power connector:




A review for the card reckons that it consumes 126 W at idle at 156W at full load (neoseeker.com)


I guess that this means I do need the 1x4 aux power onto the mobo.


After a bit more research, I don't think I can adapt the 2x2 12V power on the Hx520 loom to Molex (to reduce the number of power cables). According to Wikipedia a molex has:


Yellow +12V

Black ground

Black ground

Red +5V


The 12V 4 pin (2x2) on the HX520 main loom has two yellow wires and two black so I suspect that it is 12V only (i.e no 5V pin). However, can Corsair tech support please confirm this?

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  • 2 weeks later...

Re the 1x4 connector on the D975xbx2 mobo.


Situation is further confused by the Intel® Desktop Board D975XBX2 Technical Product Specification. Page 63 "Power Supply Connectors" states


"Auxiliary PCI Express graphics power – a 1 x 4 connector. This connector

provides the required additional power when using high power (75 W or greater) add-in cards in either or both the Secondary PCI Express x16 (electrical x8) and the PCI Express x16 (electrical x4) bus add-in card connectors."

This seems to imply that the 1x4 connector was required.


I contacted INTEL and received the following e-mail from INTEL. I'm posting it here to help anyone else who may also be confused over the conflicting info (Technical Product Specification versus Product Guide that comes with the board). The link they provide in this e-mail makes it very clear that the 1x4 is only needed if you're using a 2x10 power connector. Therefore, if you're using a Corsair power supply (with a 2x12 connector) you don't need the 1x4 and can dispense with one modular cable :biggrin: :


Thank you for contacting Intel® Technical Support. We understand that you have some questions about the 1x4 power connector.


The use of the 1x4 power connection is recommended with ATX12V power

supplies with 2x10 connections when using PCI Express video cards that

can consume up to 75 Watts.

If you have a ATX12V power supply with 2x12 connections is not

necessary to use the 1x4 power connector.


For further information please check the following website:




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