5 GPU Mining Rig PSU Problems(not enough connectors)

[mbauman89]

I have an EVGA 1300watt psu and im putting together my second rig and i just noticed my psu only has 8 connections for powering the graphics cards. I have 4 r9 270x(2-6 pin each card) and a r9 280x(1-6 pin and 1-8pin) So thats a total of 10 connections. In my 280x i found a 4 pin molex to 6 pin connector(the 2 with yellow wires in the picture) and in my 270x box they have 2 4pin molex to 1 6pin(the ones in pictures with all black wires). Will they be ok to use to power 1 connector on 2 different cards? And which ones should i use? The ones the go from 2 molex to 1 6 pin or the 1 molex to 1 6 pin? Cause if i use the 2 molex to 6 pin id need 4 molex connectors and then i wont have enough molex connector to power my powered risers. So do you think the 1 molex to 1 6pin will be ok to power one power connector and 2 different 270xs or should i be safe and use the 2 molex to 6 pin and just not connect all my powered risers? And last question will it be ok to use a powered riser without powering it? Or will i have to get the non powered version ones?

Heres a pic of the connectors-

[rsx19]

if youre going to use them us the dual molex ones on the 280 and single molex on the 270's

also you could use one dedicated pcie power along side a molex to pcie which would make the most sense to me, it also depends on if the 1300 has a single or multirail design

[mbauman89]

Yeah i was gonna use the dual molex ones on 1  6 pin connector on 2 different 270x cards. Then the other conector on the card will be the normal 6pin from the psu.  So 2 cards will have a 6pin from the psu and a 6 pin from the molex adaptor.

[mbauman89]

Does anyone think using the molex to 6 pin with the yellow wires will be fine to power 1 of the 2 6 pin connectors on 2 different 270x's? Cause I got everything hooked up and I don't have enough molex connections. My psu only has 5 molex and 3 I use to power my risers....

[Amph]

attach the two molex on two different lines, or you will melt something

[dazza12]

Do you have any SATA power connectors spare? If so, you can use a SATA to molex cable. I've used these to make up the difference.

You are running close to the limits of this PSU. You may get away with it, but as another poster has suggested you could melt something. I'd suggest a second PSU, possibly even replacing the two PSUs with two 850W+ ones to separate out the load. It would give you more connectors and would give you room to play with.

If you've got powered risers I'd suggest keeping them powered if you can. You may get away with not using power, but you may be causing yourself problems further down the line.

[mbauman89]

well i have an rm750 that i dont use. but i was planning on using it on my next rig. 270x use like 200watts and 280xs use like 250-275 right? That would bring me to 1050 and theres nothing else the uses power except the mobo and cpu which isnt more then 100. but yeah i have plenty of sata connections. could i use my rm750 or my ax1200i cables with my evga power supply? cause that would give me the extra molex cables i need since i have 3 empty ports on my power supply that i could plug in molex or sata

[dazza12]

The R270x can draw as much as 300 watts. It may be lower in general use, but when I used to use these cards I used a power monitor and it was quite close.

In any case, it's wise to take the power estimate up to the next 100 watts. Anything could cause the card to draw a higher amount.

Although the power cables from one make of PSU may fit the other, I wouldn't use them. The power rating may be different, if the gauge of the wiring differs you could end up with the PSU failing or worse the cabling burning.

There are a number of PSU connectors available on eBay that link two PSUs together - this allows the slave PSU to power up with the main PSU. I'd seriously consider using both if they're available - use one for one set of molex connectors on the card, and the other for the opposite molex connector.

[mbauman89]

i guess ill use my rm750 to power 1 card and the powered risers. as for the connectors to add a psu cant i just ground the black to the green wire on the 24pin connector on the rm750 to get it to power on and then plug in one card and the risers, then just use the button on the back to shut it off when i need to.

[mbauman89]

This connector(pic below) came in my evga psu. I can use this on my rm750 psu to make it power on correct? So i can just connect my evga 1300 to the mobo and 4 graphics cards then connect that plug to my rm750 24 connector then just connect one card to it and everything should work fine right? Id just have to use the switch on the back of my rm psu to shut it off.

[darkghost568]

Using that to jump-start your psu should work fine. I ordered one myself and use it to test my watercooling loop when I don't want power running to my cpu, mobo, etc.

[darkghost568]

Any updates?