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HD 7950 on Seasonic 520W s12II

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  • Seasonic
  • HD
  • Graphics
Last response: in Graphics & Displays
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July 30, 2013 12:46:11 AM

I've done my power calculations. The Wattage and Amps on 12V rail is okay. all I'm worried about are those PCIe connectors.

520W S12II has 6pin+8pin PCIe connector and i need 2 8pin connectors for my 7950. Technically I can use an adapter (6pin to 8 pin) but will that be safe? Can I OC?

My other choice was Corsair GS600W, but it's made by CWT, hard to trust. Or can you guys suggest any other PSU in that range (hopefully mft by Seasonic)?

More about : 7950 seasonic 520w s12ii

July 30, 2013 1:04:07 AM

Are you sure your 7950 requires two 8 pin PCI-E cable ?? what model is that? normally 7950 requires only two 6 pin connectors. Even then you can use adapter of molex to 8 pin which is safe, not sure about 6 pin to 8 pin adapter though.
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July 30, 2013 1:10:11 AM

Quote:
2 x 150 Watt 8-pin PCI Express Power Connector is Required

http://www.flipkart.com/sapphire-amd-ati-vapor-x-hd-795...

Most threads I've read strongly discourage molex to 8 pin. 6 pin to 8 pin seems to be okay, just a bit riskier.
Have you used molex to 8 pin adapters for any longer periods with full load? I read they heat up
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July 30, 2013 1:36:37 AM

Technically speaking a PCI-E 6 pin can only supply a max of 75 W of power. So how does a 6 pin to 8 pin adapter cable can supply 150W ? If it needs to supply 150W the adapter cable must contain two 6 pin in support. I believe you can use that sapphires bundled 6pin to 8 pin cable without problems as long as you dont do to much overclocking to the card. Molex to 8 pin is the safest option than 6 pin to 8 pin adapter. Since your PSU is a good quality one it will handle the card really well.

Take a look at this link as well: http://www.tomshardware.com/answers/id-1686773/molex-8p...

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July 30, 2013 1:59:28 AM

The new models from sapphire do use 2x 8 pin connectors. I think I'll just get seasonic 750 JS that has 2x8 and 2x6 pins.

pci sig is just cautious, the 6 pins can handle 150w relatively well, same 3 12v wires as in 8 pin ones
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July 30, 2013 2:47:56 AM

I am running a Sapphire 7950 boost on a Antech HGC 520 (made by Seasonic), I know there are some 7950's out there with a PCB that requries 2x8 pin PCI connectors, but the card has a TDP of 225 under the boost bios and it will run fine with a high quality 520w PSU.

EDIT The Antec HGC 520 has 2x6+2 PCI connectors.
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July 30, 2013 4:43:56 AM

I still say it's BS. I just looked on Newegg and can't find a single 7950 that needs dual 8pin plugs. I did see this one, which looks like it needs dual 8pin plugs if you look at the back of the PCB.

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

But as soon as you go to the next pic you can see that it really uses dual 6pin plugs. I really want to tell you that you are mistaken. I haven't heard of any dual 8pin 7950s. The OC'd ones use a six and eight, I've never seen or heard of dual 8pin 7950. The Seasonic 520W is a good PSUs so even IF you needed dual 8pin plugs you can use the adapter. But unless this is some sort of new card that hasn't been released yet/in the USA, then you won't need it.

Edit: Are you talking about this line from your product link?

Quote:
CrossFire Bridge Interconnect Cable, DVI to VGA Adapter, 8-PIN to 4 PIN x2 Power Cable


They aren't saying they are giving you two adapter cables, they are saying it needs two "4pin" (or "molex" plugs as they are often called.) to power the 8pin power cable.
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July 30, 2013 6:04:46 AM

Quote:
System Requirements
Supported OS Windows Vista, Windows 7
Other System Requirements PCI Express Based PC is Required with One X16 Lane Graphics Slot, 4096 MB Minimum of System Memory, Installation Software Requires CD-ROM Drive, DVD Playback Requires DVD Drive, Blu-ray / HD DVD Playback Requires Blu-ray / HD DVD Drive, 850 Watt Power Supply is Recommended for CrossFireX System, 2 x 150 Watt 8-pin PCI Express Power Connector is Required, 4 x 150 Watt 8-pin PCI Express Power Connector is Required for CrossFireX System, 64-bit Operating System Highly Recommended, Use of 3 or more Displays with AMD Eyefinity Technology Requires a Display Port-capable Panel or an AMD Eyefinity-validated Dongle


I know what 4pin/molex is. But probably you're right, the card will still draw less than 300W even with two 8 pins. A Seasonic 520W s12II will do. If it doesn't work, I'll use the 2 molex to 8 pin. I'll be upgrading to a Corsair HX850 when I crossfire anyway. Thanks
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July 30, 2013 6:48:49 AM

If you are going to upgrade anyways then I for sure would buy it. If I'm right then there is no problem. If you are right, you were going to buy a new PSU anyways right? Good luck with your build.
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