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Simple Radeon 3850 power supply question

Last response: in Graphics & Displays
December 27, 2007 4:41:32 PM


This is probably a really stupid question.

My brother has just been given a HIS ATI Radeon HD 3850 card. He has a fairly old PSU without 6 pin PSU connectors on it and I though i just needed a 4-pin Molex to 6-pin PCI-E cable/adaptor to power the card.

However on the one i bought the head for the PCI-E end does not fit. There appear to be 3 'rounded' pins and 3 'square' pins on the cable/adaptor but 4 'rounded' pins and 2 'square' sockets on the cards power socket. I'm wondering if i've been sold a 6 pin PSU to 4 pin Molex adaptor instead of a 4 pin Molex to 6 pin PCI-E?

I may be being really dense here so please let me down gently if I am.

If you need more info I can provide more but not sure what else you'd need to know.
a c 139 ) Power supply
December 27, 2007 5:51:17 PM

I think you bought the wrong adapter. And I was surprised to notice the HIS HD 3850 card didnt include a power adapter cable in the accessory pack. The picture below is the accessory pack for the Asus HD 3850.

You can see the power cable with its black PCI-e header and two 4-pin molex connectors.

A close up of a PCI-e power adapter cable:

I could not find any 3 round / 3 square 6 pin cable in the short google search I did.
December 27, 2007 6:52:14 PM

Cheers...yeah that's what i thought...just gonna check but 90% sure that it didn't include it. I'm quite suprised too that it didn't.
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December 27, 2007 6:55:55 PM

One other question, with the molex adaptor cable - when i get one - do i need to attach both molex ends or just one?
December 27, 2007 7:14:28 PM

My 3850 from DIAMOND did not include the power adapter either, local computer store had it for $6. Although I did send DIAMOND a intresting e-mail for not bundling the obvious.
a c 139 ) Power supply
December 27, 2007 7:17:43 PM

You want to attach both connectors using molex connectors on two separate cables from the PSU.
The accessory pack pictures of the HIS 3850s did not show a power adapter cable.
a c 139 ) Power supply
December 27, 2007 7:53:18 PM

It may not be necessary to use both molex connectors for the 3850. I've seen a few 3850 accessory packs with custom power adapter cables and they are the single molex to 6-pin PCI-e connector.

Acessory pack for SAPPHIRE 100226L Radeon HD 3850 512MB

The 2 molex to 6-pin PCI-e connector is probably a generic part. And it won't hurt anything to hook them both up.