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Other => CPU/GPU Bitcoin mining hardware => Topic started by: GenTarkin on April 17, 2012, 04:05:38 PM



Title: PCIe x1 -> x16 extender workaround for some mobo's
Post by: GenTarkin on April 17, 2012, 04:05:38 PM
I dont know if this is a known trick or not. But, last night I hooked up my first GPU using extender cable and for the life of me couldnt get it to work in any combination of GPU's, slots .. on my motherboard.

Turns out after further research I discovered some boards require the presence sense pins to be properly shorted by whatever device is plugged into it.
So, I discovered a trick using a wire to short the needed pins in the x1 connector on mobo, it overrides the sense function and will run w/e device is plugged into the slot regardless.
Heres the graphic:
http://blog.zorinaq.com/images/pcie-short-schematic.png


Title: Re: PCIe x1 -> x16 extender workaround for some mobo's
Post by: 01BTC10 on April 17, 2012, 04:38:33 PM
Thank's might be usefull when I receive my extenders.


Title: Re: PCIe x1 -> x16 extender workaround for some mobo's
Post by: Gomeler on April 17, 2012, 04:59:19 PM
There is a thread somewhere around here with a list of boards that require the presence pins to be shorted.


Title: Re: PCIe x1 -> x16 extender workaround for some mobo's
Post by: ARapalo on April 19, 2012, 04:25:13 AM
So far, none of the motherboards I've tried needed any tweaks to the motherboard. I saw that thread once, and I majority of the time it applies to older motherboards. Which motherboard are you using?


Title: Re: PCIe x1 -> x16 extender workaround for some mobo's
Post by: rograz on April 19, 2012, 10:09:19 PM
Had to do this for 3 slots (16x_1 16_2 8x) on both my GA-990FXA-UD5 for them to take 1x extenders in those slots when running 6 cards, so it applies to some newer boards as well.


Title: Re: PCIe x1 -> x16 extender workaround for some mobo's
Post by: GenTarkin on April 19, 2012, 11:37:17 PM
Well, I blew up the mobo I was mining on. Guess its x1 slot couldnt handle the power w/o molex injection. It was an old S939 board had laying around. So, gonna buy new mobo / cpu & RAM today probably.
Heres a question. The mobo Im thinkin bout buying is MSI 890FXA-GD65, has 4 PCIe x1 and 2 PCIe x16

It also has a 6pin PCIe power connector on board for the PCIe slots. Do you guys think this would sufficiently power all the PCIe slots, so I wouldnt have to use molex injected extenders?