Powered Risers and direct PCI-e powered gpus?

Docta

newbie

Activity: 14

Merit: 0

Quote from: philipma1957 on February 13, 2017, 01:22:24 PM

Exact make and model of gpu.

Exact make and model of mobo

Exact make and model of gpus.

Do not do any more gpus. Until you answer the questions above.

Basically some psus suck.
And some gpus suck a lot of power.

to answer what i have:

the mobo is 5 gpu setup from gpushack.. gigabyte 970a-ds3p

psu is 1300w lightning and i have two HD7970's, two saphire r9 fury's, and one R9 280x.

nothing else really attached to the motherboard except for a solid state drive, keyboard, mouse, & monitor.

Docta

newbie

Activity: 14

Merit: 0

wow! thanks for all your replies. i was hesitant to post a question like this but i just couldn't find an answer. you guys are great.

bathrobehero

legendary

Activity: 2002

Merit: 1051

ICO? Not even once.

Quote from: RentGPU on February 13, 2017, 02:22:28 PM

Quote from: bathrobehero on February 13, 2017, 01:42:15 PM

Quote from: RentGPU on February 13, 2017, 01:24:45 PM

Quote from: bathrobehero on February 13, 2017, 01:08:15 PM

You need both molex and 6 or 8 pin PCI-E on the cards.

If you don't plug in one of them the card won't work.

The molex can give up to 60-75 watts to the card (limitation of PCI-E), the 6-pin PCI-E can do another 75W and 8-pins can do 150W.

You basically have 3 options:
- get a better PSU;
- add a secondary PSU (can be tricky);
- split the 6 or 8 pin cables (NOT recommended, even if the PSU could handle it);

Whatever you do, always use powered risers.

I need to do this second tricky part you said

Because more than 1000w psu here in my country cost alot of money , i though about adding second psu i have a good electrical knowledge , put just afraid anything goes out of control can you share any details incase you have done this before , how to make the grounds common i know the separate psus will have isolated grounds , also the power on/off signal i can make a circuit to do this trick or just jumper the addition psu as i don't turn off my miners . any experience to share?? ..thx

I always avoided using dual PSUs. It just always felt fishy to me. And I always avoided cheap PSUs (using mostly EVGA Supernova G2 1300W PSUs which come with 10 years of warranty) because poor quality PSU can do some real damage and because electricity fluctuates a lot down (-5-20%) where I live. So I don't have any experience with dual PSUs but there are a lot of guides and debates how it should be done properly.

Another option would be to get an old server PSU, those are very cheap even the big ones (1-2kW) and they're designed to run 0-24 but you would need to solder some extra wires on them.

I have some old hp workstations psus , but they don't come with the 8pin pci-e so that what i have to take care and do some search about right?, i wil try to do a search about those old psu if this works it will change the game for me .

thx

As far as I know you only need 12V for the 6/8-pin so you just have to check how many amps you can pull from those PSUs on the 12V rail and do some soldering based on that.

RentGPU

sr. member

Activity: 661

Merit: 258

Quote from: bathrobehero on February 13, 2017, 01:42:15 PM

Quote from: RentGPU on February 13, 2017, 01:24:45 PM

Quote from: bathrobehero on February 13, 2017, 01:08:15 PM

You need both molex and 6 or 8 pin PCI-E on the cards.

If you don't plug in one of them the card won't work.

The molex can give up to 60-75 watts to the card (limitation of PCI-E), the 6-pin PCI-E can do another 75W and 8-pins can do 150W.

You basically have 3 options:
- get a better PSU;
- add a secondary PSU (can be tricky);
- split the 6 or 8 pin cables (NOT recommended, even if the PSU could handle it);

Whatever you do, always use powered risers.

I need to do this second tricky part you said

Because more than 1000w psu here in my country cost alot of money , i though about adding second psu i have a good electrical knowledge , put just afraid anything goes out of control can you share any details incase you have done this before , how to make the grounds common i know the separate psus will have isolated grounds , also the power on/off signal i can make a circuit to do this trick or just jumper the addition psu as i don't turn off my miners . any experience to share?? ..thx

I always avoided using dual PSUs. It just always felt fishy to me. And I always avoided cheap PSUs (using mostly EVGA Supernova G2 1300W PSUs which come with 10 years of warranty) because poor quality PSU can do some real damage and because electricity fluctuates a lot down (-5-20%) where I live. So I don't have any experience with dual PSUs but there are a lot of guides and debates how it should be done properly.

Another option would be to get an old server PSU, those are very cheap even the big ones (1-2kW) and they're designed to run 0-24 but you would need to solder some extra wires on them.

I have some old hp workstations psus , but they don't come with the 8pin pci-e so that what i have to take care and do some search about right?, i wil try to do a search about those old psu if this works it will change the game for me .

thx

bathrobehero

legendary

Activity: 2002

Merit: 1051

ICO? Not even once.

Quote from: RentGPU on February 13, 2017, 01:24:45 PM

Quote from: bathrobehero on February 13, 2017, 01:08:15 PM

You need both molex and 6 or 8 pin PCI-E on the cards.

If you don't plug in one of them the card won't work.

The molex can give up to 60-75 watts to the card (limitation of PCI-E), the 6-pin PCI-E can do another 75W and 8-pins can do 150W.

You basically have 3 options:
- get a better PSU;
- add a secondary PSU (can be tricky);
- split the 6 or 8 pin cables (NOT recommended, even if the PSU could handle it);

Whatever you do, always use powered risers.

I need to do this second tricky part you said

Because more than 1000w psu here in my country cost alot of money , i though about adding second psu i have a good electrical knowledge , put just afraid anything goes out of control can you share any details incase you have done this before , how to make the grounds common i know the separate psus will have isolated grounds , also the power on/off signal i can make a circuit to do this trick or just jumper the addition psu as i don't turn off my miners . any experience to share?? ..thx

I always avoided using dual PSUs. It just always felt fishy to me. And I always avoided cheap PSUs (using mostly EVGA Supernova G2 1300W PSUs which come with 10 years of warranty) because poor quality PSU can do some real damage and because electricity fluctuates a lot down (-5-20%) where I live. So I don't have any experience with dual PSUs but there are a lot of guides and debates how it should be done properly.

Another option would be to get an old server PSU, those are very cheap even the big ones (1-2kW) and they're designed to run 0-24 but you would need to solder some extra wires on them.

RentGPU

sr. member

Activity: 661

Merit: 258

Quote from: bathrobehero on February 13, 2017, 01:08:15 PM

You need both molex and 6 or 8 pin PCI-E on the cards.

If you don't plug in one of them the card won't work.

The molex can give up to 60-75 watts to the card (limitation of PCI-E), the 6-pin PCI-E can do another 75W and 8-pins can do 150W.

You basically have 3 options:
- get a better PSU;
- add a secondary PSU (can be tricky);
- split the 6 or 8 pin cables (NOT recommended, even if the PSU could handle it);

Whatever you do, always use powered risers.

I need to do this second tricky part you said

Because more than 1000w psu here in my country cost alot of money , i though about adding second psu i have a good electrical knowledge , put just afraid anything goes out of control can you share any details incase you have done this before , how to make the grounds common i know the separate psus will have isolated grounds , also the power on/off signal i can make a circuit to do this trick or just jumper the addition psu as i don't turn off my miners . any experience to share?? ..thx

philipma1957

legendary

Activity: 4256

Merit: 8551

'The right to privacy matters'

Exact make and model of gpu.

Exact make and model of mobo

Exact make and model of gpus.

Do not do any more gpus. Until you answer the questions above.

Basically some psus suck.
And some gpus suck a lot of power.

bathrobehero

legendary

Activity: 2002

Merit: 1051

ICO? Not even once.

You need both molex and 6 or 8 pin PCI-E on the cards.

If you don't plug in one of them the card won't work.

The molex can give up to 60-75 watts to the card (limitation of PCI-E), the 6-pin PCI-E can do another 75W and 8-pins can do 150W.

You basically have 3 options:
- get a better PSU;
- add a secondary PSU (can be tricky);
- split the 6 or 8 pin cables (NOT recommended, even if the PSU could handle it);

Whatever you do, always use powered risers.

Docta

newbie

Activity: 14

Merit: 0

i connect my gpu's directly to power using the pci-e connections located directly on my gpu's and this seemed to work ok for a while....

but now I'm expanding to 5 GPU's and I've run out of pci-e cables from my psu... should i be running power to my risers (molex) instead of directly to my cards?

are they equivalent to each other? i.e. can i power some of my risers using molex cable and power the other ones by hooking power up directly to the gpus?

thanks in advance!

Topic: Powered Risers and direct PCI-e powered gpus? (Read 620 times)