Hello, I ordered this riser @ Amazon.

https://www.amazon.it/gp/product/B00JOZ05KC/ref=oh_aui_detailpage_o02_s02?ie=UTF8&psc=1

For sure, the GPU's will be powered directly from the PSU, with a 6PIN ( +8PIN) cable, but I noticed that the 1X interface ( the one which has to be plugged to the 1X PCI slot) has a molex "socket" and a cable adapter ( molex to SATA power) is also supplied..

Should I power this interface as well or is powering the GPU enough for the task..?

Thank you
A.

You definitely want to power that as well, because the card is expecting (I believe, correct me if I am wrong on the amount) 75 watts to come thru the PCI-E bus itself, and get the rest of what it needs from the external connectors you mentioned.

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You definitely want to power that as well, because the card is expecting (I believe, correct me if I am wrong on the amount) 75 watts to come thru the PCI-E bus itself, and get the rest of what it needs from the external connectors you mentioned.

I'd agree with that.

You definitely want to power that as well, because the card is expecting (I believe, correct me if I am wrong on the amount) 75 watts to come thru the PCI-E bus itself, and get the rest of what it needs from the external connectors you mentioned.

But aren't those 75 Watts already supplied "through" the 1X slot on the Mobo and "carried" by the USB 3.0 cable to the card, or is the USB cable responsible only for data transfer between the MoBo and the GPU's ?

It is very unlikely that a USB 3 port is capable of supplying 75w, which is 15A at 5 volts and USB cables are "famously thin"

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Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

It is very unlikely that a USB 3 port is capable of supplying 75w, which is 15A at 5 volts and USB cables are "famously thin"

Make sense. The USB 3.0 specs says that max current is 0.9 A

Thanks

Andrea

It is very unlikely that a USB 3 port is capable of supplying 75w, which is 15A at 5 volts and USB cables are "famously thin"

Giggle!

Do you get the prize for understatement of the threads?


:-)


Happy fast crunchin
Martin

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See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

It is very unlikely that a USB 3 port is capable of supplying 75w, which is 15A at 5 volts and USB cables are "famously thin"

Giggle!

Do you get the prize for understatement of the threads?


:-)


Happy fast crunchin
Martin

I'm working hard on retaining the crown without blowing a fuse

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Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

You definitely want to power that as well, because the card is expecting (I believe, correct me if I am wrong on the amount) 75 watts to come thru the PCI-E bus itself, and get the rest of what it needs from the external connectors you mentioned.

But aren't those 75 Watts already supplied "through" the 1X slot on the Mobo and "carried" by the USB 3.0 cable to the card, or is the USB cable responsible only for data transfer between the MoBo and the GPU's ?

PCIe specification states
x16 slots may provide up to 75W
x8/x4 slots may provide up to 25W
x1 slots should initially provide 10W & full-height cards may request up to 25W

Some motherboard manufactures design their boards to provide a full 75W to every slot. No matter if it is an x16 or x1 slot.
Some manufactures do not even provide the power specified in the PCIe bus specification to their slots.
It is safest to always use the power connector provided by the adapter or extension cable.

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SETI@home classic workunits: 93,865 CPU time: 863,447 hours
Join the [url=http://tinyurl.com/8y46zvu]BP6/VP6 User Group[

Just remember, the only reason they are using a USB 3 cable is because it has the right number of conductors for PCI-e 1X, you cannot connect the USB3 cable to a USB3 port and expect it to work.

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In am running 3 Cards With the risers, and you need to Power the riser card trough the molex Connector in order to get the card up and working.

The risers them selves Works great for me. I've used them to get the heat out of the cabinet of the cruncher.

One thing though: Make sure the molex Connectors are in good shape. A poor or slightly sloppy or loose fitting Connection on the molex would lead to a meltdown.

Re 75W to PCIe slots used for GPU see GPU Wars thread - post 1799875

Thank you all, the risers comes with a SATA power to Molex connector, and I'm using one SATA power socket of my Corsair AXi1500 to power it.

So far so good : running one card ( GTX780i) on 16X PCI-e and one (GTX660ti) with the riser...in the next few days I will add a couple of 660ti more.

A.

I am not 100% sure about this yet, but i'll put it up here just in case:

When you run Cards off risers it seems like the drivers are more likely to suffer from crashes. I've done some rudimental tests on my cruncher, and running the main GPU from a riser gave me some headache.

When i checked the bus load for the gpu running the monitor it was always seeing a high load compared to my 2.nd card not running a monitor. I've now installed the graphic card back on the mobo in a X16 slot, and the bus load is now in the range 3-5% crunching and peaking at around 40% during load. Before the move i was seeing average loads of around 25-30% during crunching and long peaks of almost 100% during loading of tasks. Not sure if this can cause crashes, but as i remember, i've run my machine With 4 Cards a short period earlier without trouble, running 2 Cards off x16 slots and 2 off risers. Lately due to heat issues i've moved all Cards to risers. With the risers the limit was definitly 3 Cards. I'll do some long time testing to see if this could be the case.

Hi there,

I tried two different USB riser cards with molex power connectors with a bad luck - couldn't get them working.

If any of You or your relatives or friends are traveling north Europe I could gift the three first ones with a (one per traveler or a group) very well used GTX780 for free. The two first get an USB riser as a bonus.

Me.

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To overcome Heisenbergs:
"You can't always get what you want / but if you try sometimes you just might find / you get what you need." -- Rolling Stones

I am using a couple of these with success, but some motherboards simply refuse to see them on the PCIE buss.
A mobo bios update might help, or might not.

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"Freedom is just Chaos, with better lighting." Alan Dean Foster

I am using a couple of these with success, but some motherboards simply refuse to see them on the PCIE buss.
A mobo bios update might help, or might not.

Any of Your kitties coming to Europe? I'd strap back a GTX780 and some kibble with instructions to the airlines to keep good care of.

EDIT: Of the cat, of course. Would not mind the GTX vanishing of in to the Thin air (Finnainr - our 'national').

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To overcome Heisenbergs:
"You can't always get what you want / but if you try sometimes you just might find / you get what you need." -- Rolling Stones

I am using a couple of these with success, but some motherboards simply refuse to see them on the PCIE buss.
A mobo bios update might help, or might not.

Any of Your kitties coming to Europe? I'd strap back a GTX780 and some kibble with instructions to the airlines to keep good care of.

I'm afraid my two remaining kitties are much too old to be gallivanting about anymore.
But, thanks for the offer.
Meow!

---

"Freedom is just Chaos, with better lighting." Alan Dean Foster

I am using a couple of these with success, but some motherboards simply refuse to see them on the PCIE buss.
A mobo bios update might help, or might not.

Any of Your kitties coming to Europe? I'd strap back a GTX780 and some kibble with instructions to the airlines to keep good care of.

I'm afraid my two remaining kitties are much too old to be gallivanting about anymore.
But, thanks for the offer.
Meow!

Meow - see my EDIT.

I had a friendship with a cat - that friendship lasted for 17 years. MeoW!

-- for the memory of my password recovery question. --

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To overcome Heisenbergs:
"You can't always get what you want / but if you try sometimes you just might find / you get what you need." -- Rolling Stones

I am using a couple of these with success, but some motherboards simply refuse to see them on the PCIE buss.
A mobo bios update might help, or might not.

Any of Your kitties coming to Europe? I'd strap back a GTX780 and some kibble with instructions to the airlines to keep good care of.

I'm afraid my two remaining kitties are much too old to be gallivanting about anymore.
But, thanks for the offer.
Meow!

Meow - see my EDIT.

I had a friendship with a cat - that friendship lasted for 17 years. MeoW!

-- for the memory of my password recovery question. --

Well, mine are both just a couple of months away from 15yo....so, no traveling for them....LOL.

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"Freedom is just Chaos, with better lighting." Alan Dean Foster