Help! Did I buy the wrong Power Supply?

[O'shi-vash]

Link to original build post: http://linustechtips.com/main/topic/267291-first-pc-build-2000-budget/

 

I have recently bought multiple components for a new computer and i have just received my power supply

in the mail. I checked out the unit to make sure everything was in order when I noticed that the supply

only has three 8 pin outputs. The build setup that I was hoping for was to have two 970 Windforce cards

in SLI however that means they each would need 2 - 8 pin power connections.

 

I didn't notice this till now as I knew the Power supply came with four 6+2 cables and an 8 pin cable.

Was I wrong to assume that this would be enough? Do I need to Return my power supply to the

supplier and buy a different one? 

 

PartPicker had no issues with the list. Is it possible to use this Power supply using the cables available? 

 

PCPartPicker part list / Price breakdown by merchant

 

CPU: Intel Core i7-4790K 4.0GHz Quad-Core Processor  ($366.98 @ DirectCanada) 

CPU Cooler: Corsair H100i 77.0 CFM Liquid CPU Cooler  ($119.99 @ Memory Express) 

Motherboard: Gigabyte GA-Z97X-SLI ATX LGA1150 Motherboard  ($109.99 @ Memory Express) 

Memory: A-Data XPG V1.0 16GB (2 x 8GB) DDR3-1600 Memory  ($154.99 @ Canada Computers) 

Storage: Crucial MX100 256GB 2.5" Solid State Drive  ($114.99 @ Amazon Canada) 

Storage: Seagate Barracuda 3TB 3.5" 7200RPM Internal Hard Drive  ($109.98 @ DirectCanada) 

Video Card: Gigabyte GeForce GTX 970 4GB WINDFORCE Video Card (2-Way SLI)  ($419.95 @ Vuugo) 

Video Card: Gigabyte GeForce GTX 970 4GB WINDFORCE Video Card (2-Way SLI)  ($419.95 @ Vuugo) 

Case: Phanteks Enthoo Pro ATX Full Tower Case  ($99.99 @ Amazon Canada) 

Power Supply: Corsair RM 650W 80+ Gold Certified Fully-Modular ATX Power Supply  ($117.48 @ DirectCanada) 

Operating System: Microsoft Windows 8.1 (OEM) (64-bit)  ($102.98 @ DirectCanada) 

Wireless Network Adapter: TP-Link TL-WDN4800 802.11a/b/g/n PCI-Express x1 Wi-Fi Adapter  ($36.99 @ NCIX) 

 

[WoodenMarker]

The 6+2pin cables are the 8pins you're looking for the graphics cards. The (4+4) 8 pin cable are for your cpu.

[JoaoPRSousa]

Just use the 6+2 as 8 pins 

[ShadowCaptain]

SNIP

 

You can use the 6+2,

 

if you have none spare you can buy extra 8 pin cable from corsair

OR I beleive you can use a molex adapter too

[O'shi-vash]

But where do I plug in the 4 (6+2) cables into my psu? there are only three 8 pin ports on the back of it...  

 

 

I need a total of 32 pins to power my graphics cards i have enough cables that came with the psu however the psu doesnt seem

to be able to even use all of the cables at once? or am i missing something?

[O'shi-vash]

The 6+2pin cables are the 8pins you're looking for the graphics cards. The (4+4) 8 pin cable are for your cpu.

 

The psu appears to only be able to support three of the 8/6+2 pin connectors not the 4 needed to power the two graphics cards.

Can I reverse the 6+2 pin and have 6 coming form the psu with the two just plugged into the adjacent 6 pin port?

Seems kinda sketchy if i did that.... 

 

http://media.laruche.com/2013/09/corsair-rm650-2.jpg

 

 

Why does the psu even include four 6+2 cables if it can't use all of them?

[Dimwitted]

That psu isn't big enough for two 970's. You need something like the EVGA G2 750W.

[WoodenMarker]

The psu appears to only be able to support three of the 8/6+2 pin connectors not the 4 needed to power the two graphics cards.

Can I reverse the 6+2 pin and have 6 coming form the psu with the two just plugged into the adjacent 6 pin port?

Seems kinda sketchy if i did that.... 

http://media.laruche.com/2013/09/corsair-rm650-2.jpg

Why does the psu even include four 6+2 cables if it can't use all of them?

No. The 8pin block at the other end of the 6+2 cables goes into the psu--they are not. You're going to have to use a 4pin molex to 8pin adapter to have enough connectors for your cards. 

 

That psu isn't big enough for two 970's. You need something like the EVGA G2 750W.

The psu is big enough to power the cards--it just doesn't have enough connectors without an adapter.

[O'shi-vash]

That psu isn't big enough for two 970's. You need something like the EVGA G2 750W.

 

Part Picker claimed the estimated wattage was only around 500.

Or is the fact i need a 750 because of this output port problem?

[samcool55]

The psu appears to only be able to support three of the 8/6+2 pin connectors not the 4 needed to power the two graphics cards.

Can I reverse the 6+2 pin and have 6 coming form the psu with the two just plugged into the adjacent 6 pin port?

Seems kinda sketchy if i did that.... 

 

http://media.laruche.com/2013/09/corsair-rm650-2.jpg

No worries it's all fine, You can use a 6-pin cable to get 2 molex connectors, and you can convert the 2 molex connectors to a 6 or an  8 pin with the adapters that will be included in the 970's.

[O'shi-vash]

 

No. The 8pin block at the other end of the 6+2 cables goes into the psu--they are not. You're going to have to use a 4pin molex to 8pin adapter to have enough connectors for your cards. 

 

 

 

 

Im not too experienced with 4pin molex's can you link a potential option? cost? 

[WoodenMarker]

Im not too experienced with 4pin molex's can you link a potential option? cost? 

It should look like this:

 

Where are you shopping/located?

[Grrizz]

Don't you have 2x6+2 pin connectors on each cable?

650W will be enough power for that system.

[O'shi-vash]

It should look like this:

 

 

Where are you shopping/located?

 

I'm Near Vancouver, BC, Canada.

I can easily drop by an NCIX tomorrow if they would have what im looking for?

[WoodenMarker]

Don't you have 2x6+2 pin connectors on each cable?

Oh yeah--not sure how I forgot that and to mention it in the first place.

There should be a total of 4 x 6+2 cables which should be enough for the 2 cards.

[O'shi-vash]

Don't you have 2x6+2 pin connectors on each cable?

650W will be enough power for that system.

 

 

So it appears that I have a few cables that are 8 pin to 6+2 and an additional 6+2

 

This means that i could technically plug everything in however that seems very sketchy to run 8 pins from the power supply to 16 pins on the gpu.... with one cable 

[WoodenMarker]

So it appears that I have a few cables that are 8 pin to 6+2 and an additional 6+2

This means that i could technically plug everything in however that seems very sketchy to run 8 pins from the power supply to 16 pins on the gpu.... with one cable 

They aren't 1:1 pins--that's how they work. 

[O'shi-vash]

Thank you very much. I feel very embarrassed that i didn't inspect the cables further before jumping to conclusions. 

 

Thank you all for your help and such an incredibly quick response!!!

[Grrizz]

So it appears that I have a few cables that are 8 pin to 6+2 and an additional 6+2

 

This means that i could technically plug everything in however that seems very sketchy to run 8 pins from the power supply to 16 pins on the gpu.... with one cable

That's fine, the cables are rated to 300W each and the outputs are rated to 150W each mainly because of the landings on the PCB itself and not the cables/connectors. Each card will draw much less than 300W too, the default power limit from the card for the cables is 225W and 250W total but you should be using much less than that at stock clocks.

[Guest]

Shame you didn't go with the EVGA Supernova G2 750W that I suggested in your other thread. Way better than the Corsair RM, and currently cheaper as well. It is $104.98 at Newegg after rebate.