PCI-E splitters don't work!!

[dragonmike]

So I got myself an Onda D1800 board with 6 powered slots. To juice it up and the six Vegas that I plugged onto it I got an EVGA 1600 G2.

Unfortunately it doesn't have enough PCI-E connectors. It's got a few single 8pin and some 8+6 pin connectors. Unfortunately every Vega needs 2x 8pin each.

So I got myself a few 6-to-8 connectors and 8-to-2x8 splitters/adapters.

But to my great displeasure, the PSU won't power up at all if ANY of these are used!!

Dafuq?

Why? WHY? What do I do now?? EVGA don't sell connectors afaik!...

[Vann]

Never use a PCI-E 8-pin splitter to power dual 8-pins. That's a good way to overload your PSU cable and rail with close to 300 W. I use PCI-E splitter cables with 8-pin + 6-pin on the same GPU or with dual 6-pin for risers but never with dual 8-pin connectors.

You either need to add another PSU with enough PCI-E connectors for the VGA inputs and use a dual ATX splitter cable so they come on and off together or use a large enough server PSU with enough PCI-E connectors and a Pico adapter for the 24-pin, CPU and Sata connectors.

https://www.aliexpress.com/item/2017-New-Arrival-30cm-24Pin-Dual-PSU-ATX-Power-Supply-Sync-Starter-Extender-Cable-For-BTC/32825280357.html?

[dragonmike]

But those powerful PSUs are single rail... And EVGA is providing dual 8-pin cables with the 750GQ's so it can't be that bad? But if all that fails I suppose I'm going to have to send back that 1600G2 and get something else. Although that does sound a bit fukced up.

[P00P135]

Maybe you got the wrong type of splitters and they are shorting the PSU?

[Vann]

By rail I mean the PCI-E connector on the PSU. The rated power specification for a PCI-E 8-pin connector is up to 150 W and 75 W for a 6-pin connector. No PSU PCI-E connector or cable is designed to pull 300 W from a single connector.

[P00P135]

By rail I mean the PCI-E connector on the PSU. The rated power specification for a PCI-E 8-pin connector is up to 150 W and 75 W for a 6-pin connector. No PSU PCI-E connector or cable is designed to pull 300 W from a single connector.

I like when people quote stuff from 2005 and think its correct.

[philipma1957]

send the psu back

buy this one


http://www.corsair.com/en-us/ax1500i-digital-atx-power-supply-1500-watt-fully-modular-psu


I will link the proper cables

look at this photo

10 jacks  use 1 for your cpu cable use nine for pcie

corsair sells  pcie cables with 2   8 pin heads

I will find link

[Vann]

By rail I mean the PCI-E connector on the PSU. The rated power specification for a PCI-E 8-pin connector is up to 150 W and 75 W for a 6-pin connector. No PSU PCI-E connector or cable is designed to pull 300 W from a single connector.

I like when people quote stuff from 2005 and think its correct.

What you may like and what reality is are two different things. The PCI-E System Power Delivery Requirements (page 14) calls for 12.5A from a 2x4 connector (8-pin) and 6.25A from a 2x3 connector (6-pin)

https://us.v-cdn.net/5021640/uploads/editor/yr/f1z842765sj9.pdf

12.5A x 12V = 150 W

[philipma1957]

send the psu back

buy this one


http://www.corsair.com/en-us/ax1500i-digital-atx-power-supply-1500-watt-fully-modular-psu


I will link the proper cables

look at this photo

10 jacks  use 1 for your cpu cable use nine for pcie

corsair sells  pcie cables with 2   8 pin heads

I will find link

comes with
Cabling - Corsair AX1500i
Type of Cable   Length from PSU
Modular Cables
20+4 pin ATX connector   700mm
4+4 pin EPS/ATX12V   800mm
4+4 pin EPS/ATX12V   650mm
6+2 pin PCI-E, 6+2 pin PCI-E   700+150mm
6+2 pin PCI-E, 6+2 pin PCI-E   700+150mm
6+2 pin PCI-E   650mm
6+2 pin PCI-E   650mm
6+2 pin PCI-E   650mm
6+2 pin PCI-E   650mm
6+2 pin PCI-E   800mm
6+2 pin PCI-E   800mm
5.25" to 3.5" adapter   100mm
5.25" to 3.5" adapter   100mm
5.25"+5.25"+5.25"+5.25"   450+100+100+100mm
5.25"+5.25"+5.25"+5.25"   450+100+100+100mm
5.25"+5.25"+5.25"+5.25"   450+100+100+100mm
SATA+SATA+SATA+SATA   550+95+95+95mm
SATA+SATA+SATA+SATA   550+95+95+95mm
SATA+SATA+SATA+SATA   500+95+95+95mm
SATA+SATA+SATA+SATA   500+95+95+95mm
SATA+SATA+SATA+SATA   500+95+95+95mm
I2C    800mm
Mini USB to USB Mainboard Header   800mm
Unit Dimensions (L x W x H)
224mm x 150mm x 86mm

has 6 single cables
has 2 double cables

has room for 1 more cable

buy a few   
http://www.corsair.com/en-us/type-3-flat-black-ribbon-cable-pcie-6-2-pin-dual-connectors-compatible-with-all-type-3-pin-out-psu

[TheYankeesWin!]

Hey  phil good info.

I have a follow up


It has two double headed pcies  and 6  single pcies,

So he buys a few dual headed  say 3  giving him 2 spares.

He has three dual plugged in and six single.

So send a single to each of the 6 cards.
Then use  each dual on 2 cards.

This means 1.5 cables per card.
1 Single and 1/2 of a dual.
It should  provide the best power possible to each card.

[P00P135]

By rail I mean the PCI-E connector on the PSU. The rated power specification for a PCI-E 8-pin connector is up to 150 W and 75 W for a 6-pin connector. No PSU PCI-E connector or cable is designed to pull 300 W from a single connector.

I like when people quote stuff from 2005 and think its correct.

What you may like and what reality is are two different things. The PCI-E System Power Delivery Requirements (page 14) calls for 12.5A from a 2x4 connector (8-pin) and 6.25A from a 2x3 connector (6-pin)

https://us.v-cdn.net/5021640/uploads/editor/yr/f1z842765sj9.pdf

12.5A x 12V = 150 W

16AWG cables can provide up to 400w.  Modern day PSU's provide these and give you dual 6-8pin connections on one cable.  Stop regurgitating old google info.

[Vann]

By rail I mean the PCI-E connector on the PSU. The rated power specification for a PCI-E 8-pin connector is up to 150 W and 75 W for a 6-pin connector. No PSU PCI-E connector or cable is designed to pull 300 W from a single connector.

I like when people quote stuff from 2005 and think its correct.

What you may like and what reality is are two different things. The PCI-E System Power Delivery Requirements (page 14) calls for 12.5A from a 2x4 connector (8-pin) and 6.25A from a 2x3 connector (6-pin)

https://us.v-cdn.net/5021640/uploads/editor/yr/f1z842765sj9.pdf

12.5A x 12V = 150 W

16AWG cables can provide up to 400w.  Modern day PSU's provide these and give you dual 6-8pin connections on one cable.  Stop regurgitating old google info.

Where are you getting 16 AWG cable can provide up to 400 W? According to this wire capacity chart the maximum rating for 16 AWG cable is 20A for a short run which at 12V is 240 W. Stop claiming your fantasies as fact, it's dangerous. The fact that some PSU's come with dual 8-pin PCI-E cables and connectors which ARE intended for 150W each, doesn't mean it's a good idea to use them for a mining rig which is under constant high load 24/7.

20 A x 12 V = 240 W

http://www.rowand.net/shop/tech/wirecapacitychart.htm

[dragonmike]

They're under constant load, yes, but at lower voltage. Mining cryptonight also so there will be no way near 300W load per cable. Not even 200 if reports of miners using Vega are to be believed.

Phil, thanks a lot for the links and suggestions, much appreciated. If I can't get the EVGA to work, I'll get the Corsair... Or a couple of 850's.

[RIGED]

i've been where you are.
ended up with 2 EVGA 1600 to power 8 VEGA64's on an ASUS B250mining mb (overkill), thinking i would add VEGA64's with the ASUS update to support more than 8 VEGA's on this mb

i am also using GQ 6 - 6+2x2cables from the 2 EVGA 1000 i also bought(but you cant use G2 cables on these only GQ). Each card is using around 180W (with -20 voltage and other tweeks on wattman ) and achieving a very stable 43,7MH/s on each GPU

whatever you do, if using more than 1 PSU for 1 rig, make sure they are identical otherwise you will propably have problems

happy mining

[dragonmike]

Found out that only the 8-pin to 2x-8-pin splitters don't work. The 6-to-8 adapters are fine, so phew, I have just enough cables and that PSU will do the job just fine!