Do I really need to connect both 6-pin pcie power connectors?

[FuriousGeorge]

I have a BFG 250 which is flying solo right now. I couldn't believe that I needed to connect two pcie molexes to it, so I only connected one.

And it works.... so far. I haven't even installed the nvidia driver yet, though.

If it works with one, why should I hook up the second one? What can potentially happen if I don't?

[Quailane]

Nothing can potentially happen. You will be fine. I think its in case you have one of those PSU's with many +12 volt rails so that it doesn't exceed or get close to the maximum current draw for a single rail.

[Old Thrashbarg]

Theoretically you could probably even get away with only having two pins connected... the PCIe power connectors just consist of two 12V wires, 3 ground wires, and a blank. The additional wires are, I'm assuming, just so you don't have the full current load running through one wire/tiny pin connector. Why they didn't just design it to use more robust connectors and fewer pins, I dunno.

As for the second power connector, I'd never really understood the purpose, but the PSU rails explanation makes sense.

[rainless]

Wait a minute... this is insane.

He hasn't even INSTALLED THE DRIVER YET!

Of course it's going t work without the driver installed!

Play through the first couple levels of Crysis or Fallout 3 and let us know if it's still working...

[ratbuddy]

No kiddin. Without the driver, it's just working as a regular VGA (or is it SVGA these days?) card. Install the driver and see if it still works..

Er..

Meh, what rainless said.

[Mr.Guvernment]

ya, do you think they put it on there for the fun of it? they put it on for a reason, stress the card in 3d mode and get back to us.

if they didnt need it, they would of saved the money and not added the parts for the 2nd one.

[FuriousGeorge]

All you answers make sense. Thanks guys.

[PhoenixOfChaos]

Yep at what rainless said. It probably doesn't exceed like 1% load while on desktop mode. It could probably draw that power from a AA battery ;)

[mxthunder]

My PC wont even boot if either of them is not connecting. it makes a scary beeping sound

[Zantal]

My PC wont even boot if either of them is not connecting. it makes a scary beeping sound

M8 3 years ago when i bought my 8800 ultra i literally ****ed my pants off when it made that sound.

it took me about 20 minutes to figure out why :p

was the first time i used pci-e coming from agp :beer:

[freeagent]

you dont like that squeal? ocmon :)

i know the first time i heard it too i dam near **** myself :)

after that it was just annoying.. i havent tested my 285 for that yet..

[Froggy]

I think he is talking about the no post beep when the video card isn't properly seated or the PCI-E is not plugged in on a high end card that needs that much power to boot.

As far as why not less connections/pins it has to do with wire size. The std. PSU wire size will not carry enough amps/watts so that have to distribute the watt load amongst many wires.

[Quailane]

I think he is talking about the no post beep when the video card isn't properly seated or the PCI-E is not plugged in on a high end card that needs that much power to boot.

As far as why not less connections/pins it has to do with wire size. The std. PSU wire size will not carry enough amps/watts so that have to distribute the watt load amongst many wires.

After digging into this I see you right, sort of. The specification rates the power connector at only 75 watts, the same as the PCI-E slot itself. However, that rating is ridiculous. Each of those aluminum 18 AWG wires is rated conservatively at 9 amps. Many of those connectors have 3 +12V lines, but some have two. That is either 18 or 27 rated amps of +12V current. That is 216 watts minimum or 324 watts maximum for each PCI-E power connector. That plus the 75 watts of power available from the slot itself gives way more available power than most graphics cards ever need. For example, my HD4850 is rated at a TDP of 110 watts and the OP's GTS 250 has a TDP of 150 watts. Just for reference, even the GTX 295 has a TDP of 289 watts.

[Froggy]

I agree with you. I am under the assumption that all the quality PSU's we all buy use larger AWG wires. I wonder what the minimum specification is? Maybe it is the connector that is the limitation.

Isn't a molex connector limited to something around 36 watts which is way less than any wire can handle.

Plus one would have to factor in voltage drop over a longer power lead. I am sure it is over specced, but that is for our benefit for sure.

[ChanceCoats123]

To end all this, I would like to point you to furmark (http://www.ozone3d.net/benchmarks/fur/).