Should you use 6 pin pcie power connectors?

[William Murphy]

I am upgrading my computer and one of the things I am going to get is a power supply. I am planning on getting two hd 6850s and running them in crossfire. I already have one. This however would require four 6 pin pcie power connectors. Most power supplies either have one or two 6 pin graphics card connectors. There are molex to 6 pin adapters that you can get. I already have a few which came with motherbaords and graphics cards. Is it worth spending the extra money to get a psu with 4 connectors or can I get a cheaper one which does not have as many connectors and use the adapters. Also what wattage should I get. I will be getting the i5 3570k, azrock extreme4 motherboard and as I have said I will have 2 hd 6850. I only have one hard drive and one optical drive. I am worried about using the adapter because I read somewhere that it is not recomended to use them but it did not give a reason for this.

What power supply would you recommend? I live in the uk so I can not use new egg.

 

[Traildriver]

For PSU size try this:
http://extreme.outervision.com/psucalculatorlite.jsp

Youshould be more concerned that the PSU is providing enough amperage on the 12V rail for all the components.

As stated in many responses for other PSU questions never cheap out on a PSU. Get a quality name brand. In your case, research any of the newer units that are modular in design ie the ability to attach needed cabling. Or leave them off if not required.

 

[Robi_g]

OCZ ZS750 as that has 2x6pin and 2x6+2pin, Novatech and ebuyer sell them.
I wouldn't use the adapters as I just don't trust them, no real reason for it but I just don't.

 

[pdxalex]

I think you'll find most reputable PSUs meeting your wattage requirements will come with 4x PCI-E connectors anyhow. Something like this 750W:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139021

Sorry, I know you can't use newegg, I just linked to it for the description

 

[Rugger]

A system with two HD 6850 GPUs running in crossfire mode requires a 600W PSU with at least 40A on the 12V rails and four 6-pin PCIe power connectors. Most PSUs below 700W do not have four PCIe power connectors but actually have sufficient amperage to run moderate CF/SLI setups like your planned CF of 6850s. A great PSU for you to consider is the Corsair Enhusiast TX650W V2: http://www.scan.co.uk/products/650w-psu-corsair-enthusiast-series-650txv2uk-85-eff-80-plus-bronze-sli-crossfire-eps-12v-quiet-fan-a#ProductFeatures
It has two 150W 6+2 pin PCIe power connectors. The 6-pin PCIe power connectors are rated at 75W. You can put a splitters on Corsair's two 6+2 Pin PCIe connectors to get a total of four PCIe power connectors. Example of a splitter: http://www.amazon.com/Cable-CB-PCIE8-Y-Connectors-Sleeved-PCI-Express-connectors/dp/B005H3IIEA/ref=pd_sxp_grid_pt_1_0

The 6+2 pin PCIe cables are rated at 150 W, so they can safely provide power to two 75W 6-pin PCIe connectors.

 

[delluser1]

XFX 650 has 4 pcie connectors
http://www.scan.co.uk/products/650w-psu-xfx-pro-series-core-edition-p1-650s-ukb9-85-eff-80-plus-bronze-sli-crossfire-eps-12v-fan-at

 

[Rugger]

You know...I actually looked at that because I thought that it had enough connectors; I saw the two 6+2 and completely missed the two 6-pins.

William: I would recommend a PSU that comes with sufficient connectors from the factory. The XFX Pro 650W that Dell recommended is an excellent PSU with more than enough power for your planned build and I second his recommendation.

 

[yummerzzz]

What?!

A HD 6850 only needs 1 power connector...

 

[delluser1]

What?!

A HD 6850 only needs 1 power connector...

A few of the higher end models need 2 and it's not a bad idea to have the extra's for upgrade purposes

 

[William Murphy]

What?!

A HD 6850 only needs 1 power connector...

The one that I have requires two. I have the asus version of the hd 6850

 

[William Murphy]

You know...I actually looked at that because I thought that it had enough connectors; I saw the two 6+2 and completely missed the two 6-pins.

William: I would recommend a PSU that comes with sufficient connectors from the factory. The XFX Pro 650W that Dell recommended is an excellent PSU with more than enough power for your planned build and I second his recommendation.

Do you have opinion on using the molex to 6 pin pcie adapters?

 

[William Murphy]

A system with two HD 6850 GPUs running in crossfire mode requires a 600W PSU with at least 40A on the 12V rails and four 6-pin PCIe power connectors. Most PSUs below 700W do not have four PCIe power connectors but actually have sufficient amperage to run moderate CF/SLI setups like your planned CF of 6850s. A great PSU for you to consider is the Corsair Enhusiast TX650W V2: http://www.scan.co.uk/products/650w-psu-corsair-enthusiast-series-650txv2uk-85-eff-80-plus-bronze-sli-crossfire-eps-12v-quiet-fan-a#ProductFeatures
It has two 150W 6+2 pin PCIe power connectors. The 6-pin PCIe power connectors are rated at 75W. You can put a splitters on Corsair's two 6+2 Pin PCIe connectors to get a total of four PCIe power connectors. Example of a splitter: http://www.amazon.com/Cable-CB-PCIE8-Y-Connectors-Sleeved-PCI-Express-connectors/dp/B005H3IIEA/ref=pd_sxp_grid_pt_1_0

The 6+2 pin PCIe cables are rated at 150 W, so they can safely provide power to two 75W 6-pin PCIe connectors.

Do you think it would be better to use a splitter than a molex to 6 pin pcie adapter which I already have?

 

[Rugger]

You should be good using the molex adapters.