Question Graphics card with 2 x 6-pin power connectors ?

[silversmithy]

Hopefully this is the proper place for this..

Anyway I have installed graphics cards before, but I get a little nervous when I'm testing with a modular PSU of unknown background. I had a chip on a GTX 980Ti flame out the first time I tried using extra connections on a past modular PSU so hoping not to duplicate. I had double checked proper cable connections, correct cables for the specific PSU, etc., but still it happened. It was a used 980 so hard to know.

Anyway I recently purchased some used components and want to test each out. I have an old PC in a big case with an nforce 680i lt sli motherboard that has space so it's easy to install and remove things. Running Windows 7 ultimate 64 bit, single DVD, and first of all I am using an old GTX 460 to test a used supernova 850 watt PSU. The 460 has 2 x 6-pin connectors on it. I was going to just use the cable that has one 6-pin, and one 6+2 pin coming off of it, but I've heard it's best to use 2 different cables, 1 each for each connector. I have another single 6+2 cable so I plugged in 1 cable to one of the 4 vga connections on the PSU, and the 2nd cable into a different vga connection. On the PSU. This seems right, but last time I did well you know... 980Ti toast. I've made doubly sure I've got the exact right cables into the exact right connections, but I am very nervous considering past experience. I realize that cables are NOT interchangeable.

Please advise. Thank you.

 

[Lutfij]

I'm testing with a modular PSU of unknown background
Please elaborate on this.

In fact, please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model.

but I've heard it's best to use 2 different cables 1 each for each connection.

 

[silversmithy]

I knew I forgot something.

the CPU is an Intel core 2 duo, if I remember an e6750? 2.67Ghz. yeah I know.

stock Intel cooler

Nvidia 680i lt sli motherboard

4gb ram

3.5 inch std HDD 80GB.. testing machine so not much to store on it.

GTX 460

EVGA supernova G2 850 watt PSU

Cooler Master large blk case with brushed aluminum front. I don't know the exact model/style.

Windows 7 ultimate 64 bit

Samsung 32inch smart TV.

This is mainly just a testing PC.

This is the same case and motherboard that the 980Ti bit it in so that's why Im nervous.

I currently have it all set up like the second pic from the left.

Thank you.

 

[CountMike]

I knew I forgot something.

the CPU is an Intel core 2 duo, if I remember an e6750? 2.67Ghz. yeah I know.

stock Intel cooler

Nvidia 680i lt sli motherboard

4gb ram

3.5 inch std HDD 80GB.. testing machine so not much to store on it.

GTX 460

EVGA supernova G2 850 watt PSU

Cooler Master large blk case with brushed aluminum front. I don't know the exact model/style.

Windows 7 ultimate 64 bit

Samsung 32inch smart TV.

This is mainly just a testing PC.

This is the same case and motherboard that the 980Ti bit it in so that's why Im nervous.

I currently have it all set up like the second pic from the left.

Thank you.

For GPUs that use less than 180-200W it's safe to use single PCIe cable that branches in 2 connectors. Potential problem is in wires that can overheat or not supply enough power due to resistance. Older and cheaper PSUs may have thinner wires so that's another consideration

 

[peterf28]

I have similar issue : my psu has only one 6 pin pcie power connector. If I underclock and set low power limit on my 1070Ti which has 6pin and 8pin power connectors, and connect only the 6 pin connector, will it work? I plan to limit the gpu power limit if it is possible in afterburner.

(This is not my main rig, just a backup rig which I use occasionally. I do not plan to push the GPU, will use it only for older games)

 

[CountMike]

I have similar issue : my psu has only one 6 pin pcie power connector. If I underclock and set low power limit on my 1070Ti which has 6pin and 8pin power connectors, and connect only the 6 pin connector, will it work? I plan to limit the gpu power limit if it is possible in afterburner.

(This is not my main rig, just a backup rig which I use occasionally. I do not plan to push the GPU, will use it only for older games)

No, you should have all power connectors on the GPU even if you have to use adapter for them.Also can't trust SW to keep critical settings,

 

[silversmithy]

I'm testing with a modular PSU of unknown background
Please elaborate on this.

In fact, please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model.

but I've heard it's best to use 2 different cables 1 each for each connection.

So I have the PSU cables connected to the 460 just like in the top image 2nd from the left. I'm pretty sure that's the way I had the 980Ti connected to a reliable/stable 750 watt 80 plus gold PSU and one of the chips fried. The 460 will be my dedicated testing GPU so I hate to lose it or any other components. Anyway if there's something I'm missing please let me know. Thank you.

 

[hotaru.hino]

The whole thing with "don't plug in a pig-tailed cable to handle one video card" doesn't make sense to me, at least for a PSU that isn't questionable.

For instance, my Corsair RM850x came with 2x8-pin cables. If it was dangerous to use 2x8-pin at their maximum specified capacity of 300W, why would Corsair include this? They have a reputation to uphold. And they may be overbuilt for the application in question. To quote from Jon Gerow:

A quality PSU like a Corsair, Seasonic, beQuiet, etc. will tend to use what is called Mini-Fit HCS (stands for “High Current System”). These terminals are specified to support 8.5 to 10A of current each (see dual row with 16 AWG and 18 AWG wire in the Molex Mini-Fit PLUS HCS spec). This makes the connectors actually more capable than the 12VHPWR connector. Even if Mini-Fit Jr. is used instead of HCS, the rating is A LOT higher than 150W per connector.

8.5-10A per pin (terminal) is 102-120W per pin, or up to 360W for the connector. Even if they used the same spec for the PSU connecting side, there's still 60W left of headroom. Though I guess this could be an issue if you use a single cable on a card known for having massive power spikes. Which in this case, would be something like a Radeon 6950XT.

If you want to play it safe, sure, use separate cables for each socket on the card. But you don't need to do that.

 

[silversmithy]

Is there any danger of using 2 separate cables with it putting out too much power??? I'm pretty sure that I used 2 separate cables from a different semi modular PSU and like I mentioned before that card fried. The PC I'm currently using had that original PSU running a GTX 750 Ti without any issues. Of course that only had one additional 6 pin I believe. I just don't want to fry anything again.

 

[DSzymborski]

Is there any danger of using 2 separate cables with it putting out too much power??? I'm pretty sure that I used 2 separate cables from a different semi modular PSU and like I mentioned before that card fried. The PC I'm currently using had that original PSU running a GTX 750 Ti without any issues. Of course that only had one additional 6 pin I believe. I just don't want to fry anything again.

No, that's not a thing.

 

[boju]

I used 2 separate cables from a different semi modular PSU and like I mentioned before that card fried

Only if you used a pcie cable not designed for that psu, as in a cable bought off the shelf or from a different power supply.

There should be a warning sticker on semi/full modular psus of potential failures if use cables not designed for it. Sadly not, and people do often get caught out, because you would think a pluggable cable that fits are universal. Should be, but isn't so. What happens is you have psu makers put positive/negative pins in different spots at psu end and if you use a cable not intended for that model to correct wire output to the component you'll have power zapping to where it shouldn't then frying it.

 

[silversmithy]

Understood. I did know about modular PSU cords being very specific, but good reminder. Thanks