# Why do 6 pin pcie adapters have 2 molex leads?



## shevanel (Dec 29, 2009)

just wondering why 2 molex = 1 6 pin pcie

How much power does a single 6 pin from a psu supply to a gpu and how much does a molex provide?

thanks


----------



## EnergyFX (Dec 29, 2009)

You are technically supposed to plug the molex into two separate lines from the PSU, not just plug two daisy-chained molex plugs.  Count the wires.  If you had a designated 6 pin plug then you would have 6 wires running all the way back to the PSU.  One molex is only 4 wires (of which only one is a +12V and two are ground). A 6 pin pcie has three +12V and two or three grounds depending on the manufacturer. If you take a shortcut and simply plug two daisy chained molex plugs into the adapter then in reality you are only feeding the pcie plug with a single +12V and two ground conductors... which could possible load the conductors with too much amperage.

In reality... I haven't had an issue with it, but I am an electrician and have a better understanding than most when it comes to conductor ampacity.  I recommend you use separate circuits that run all the way back to the PSU unless you are confident of how you are loading the conductors.

EDIT: tried to correct myself, but my memory is too fuzzy.


----------



## shevanel (Dec 29, 2009)

I'll show you what lead me to ask this question.

In the comments of this video scroll down to bigbadddouchebags comment and you'll see why I had this dumb look on my face when I waltzed in here to ask this question.


----------



## EnergyFX (Dec 29, 2009)

Actually my memory fails me... a pcie cable has three +12V and two or three grounds depending on manufacturer.  It's been a while since I had to build/wire up a cable so I can't quite remember how it all matches up... but the main point is still the same... it comes down to amperage loading of the conductors.


----------



## EnergyFX (Dec 29, 2009)

shevanel said:


> I'll show you what lead me to ask this question.
> 
> In the comments of this video scroll down to bigbadddouchebags comment and you'll see why I had this dumb look on my face when I waltzed in here to ask this question.



WTF??



			
				BigBaddGaming on YouTube sight (follow link) said:
			
		

> lol my 5770 gets 40 to 50 fps in crysis very high with any gfx mod using the dual six pin power connector that came with it.People just dont think to use the 1 that comes with it and wonder why they only get 30 fps like i get 300 in oblivion all the time with open cities but only 14 using my 3870's power connector



:shadedshu either he is trying to get something started simply for laughs or, more likely, he is an absolute moron and has no clue whatsoever about what he is talking about.


----------

