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Radeon HD 5850 DirectCU power issues

Last response: in Graphics & Displays
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January 7, 2013 4:16:09 PM

I just bought a radeon HD 5850 Direct CU for a budget build and it has a 6pin pci-e power socket and a 8pin pci-e power socket on it.

The question is do i need both a 6 and 8 pin pci-e power cable attached to it for it to operate as at the moment i only have a 6pin pci-e connector.

Please note i would have fired it up by now but waiting for cpu and ram to arrive wed, and would like to know if i need to go and get an adaptor?
January 7, 2013 4:19:40 PM

if it came with a 6 and an 8 you use a 6 and an 8.
January 7, 2013 4:20:14 PM

it only came with a 6.....
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January 7, 2013 4:22:48 PM

Yeah you need both plugged in for the card to work. If it only has a 6-pin it probably isn't powerful enough for your card. Don't try it until you (or we) confirm your PSU can handle your card. Individual cards vary a little but AMD recommends a minimum 500w PSU. What is your PSU?
January 7, 2013 4:23:13 PM

well you better return that power supply and get a better one that is rated 550w-600w
January 7, 2013 4:25:09 PM

i got a 700w psu, with a 6pin pci-e and 3 4pin molex, so should i go buy a 8 pin pci-e power cable?
January 7, 2013 4:25:46 PM

its a 700w ace black edition psu
January 7, 2013 4:32:49 PM

Any quality 700 watt power supply should at least have more then 1 x 6 pin PCI-E cable.

I can see a lack of an 8-pin on some older ones, but 1 single 6 pin is just strange.

I mean my 300 watt power supply has 1 x 6 pin.

Seeing that power supply for £17.50 on amazon is also a bit scary. Quality power supplies just do not get THAT cheap.
January 7, 2013 5:07:59 PM

like a said budget build, i went on price - perfomance and reviews. am prob going to upgrade to a corsair in the future.
January 7, 2013 5:10:57 PM

If the power supply can deliver its rated ~450-480 watts at 12 volts, the card would run with Adapters. You will certainly want both connectors (6 and 8 pin.). The power supply has the 6 pin covered, but you need an adapter to get the 8 pin.

In the future, budget on anything but the power supply. A bad power supply can take out the full system if it fails.
January 7, 2013 6:08:25 PM

bwooly1001 said:
i got a 700w psu, with a 6pin pci-e and 3 4pin molex, so should i go buy a 8 pin pci-e power cable?



you're going to need it. ( dual 4pin molex to 8pin pci-e "Y" adapter )
January 7, 2013 6:22:20 PM

so will the gfx card work with only the 6pin?

why does it require the second power connection if it didnt come with the molex adaptor?

it only came with a 6pin molex (which i dont need)
January 7, 2013 6:37:47 PM

bwooly1001 said:
so will the gfx card work with only the 6pin?

why does it require the second power connection if it didnt come with the molex adaptor?

it only came with a 6pin molex (which i dont need)


No it won't work with only the 6pin. Both are there for a reason.

We're not Asus, we don't know why it didn't come with an 8pin adapter.
January 7, 2013 6:39:41 PM

no matter what way YOU want it, there's only one way to use it. the right way. pony up and get the cable or suffer.
January 7, 2013 6:41:18 PM

lol no need to get defensive, im wanting this build to run well as its my first.
I have just phoned a m8 who has got me one,
thank you all for your help.
will post with results wed
January 7, 2013 6:43:37 PM

was asking why it needs both cables as i was hoping someone would be able to answer me and then maybe i would learn something about gpu's i obviously dont know.....
January 7, 2013 6:48:58 PM

bwooly1001 said:
was asking why it needs both cables as i was hoping someone would be able to answer me and then maybe i would learn something about gpu's i obviously dont know.....


That card needs around 175W of power, which is more than a single 6 pin can supply, and the 8/6 pin combo probably worked best. It's a bit older card, where 8 pin was still popular. I think all cards now use only variations of the 6 pin connector, to standardize it a bit, but in the early days, cards had 6 pin, 8 pin, some just put molex plugs on the card, they were all over the map.
January 7, 2013 6:50:54 PM

thank you very kindly sir, i have all the connections needed to run this now.

and also the knowledge to travel forth int the great world of building pc's lol
January 7, 2013 7:02:16 PM

Asus rates the card at upto 225 watts.

Quote:
Power Consumption up to 225W2 additional 6 pin PCIe power required


6 pin connectors give 75 watts while the 8 pin is good for 150 watts and the motherboard's PCI-E slot can deliver 75 watts.

For whatever reason they decided to go with both, but from the looks of it, you will need both connected to power the card.

The normal, non overclocked card did not need all this.
January 7, 2013 7:13:01 PM

5850s usually come with two 6-pin power connectors. 6-pin connectors are capable of supplying 75W, 8-pin connectors can supply 150W, and the pci express slot itself can supply 75W. You normally won't see an 8-pin connector on cards that use less than 225W, and 5850s use considerably less than that. It's possible ASUS opted for an 8-pin instead of a second 6-pin so heavy overclockers could get enough juice. That's just me speculating, but you will need to use both power connectors.
January 14, 2013 10:55:20 AM

You will be glad to know this psu blew and I am now needing a new one any suggestions for running this gfx card, its on a m5a99x EVO r2.0, with a amd fx 6100, a thermaltake water performer 2.0 and 3 Molex fans.
January 14, 2013 4:19:28 PM

Tis k got an ocz sz 650w
January 14, 2013 4:40:18 PM

Are you up and running now?
January 14, 2013 4:49:23 PM

No picking it up in the morning
!