MP 7,1 External PSU for 7,1 available?

[LEOMODE]

make sure its a corsair one as some have different pin outs at PSU so check the corsair chart to what cable suits your PSU part number.

https://www.corsair.com/us/en/s/psu-cable-compatibility

Looked like the cable you mentioned was included in the Corsair PSU package as per the attached photos. So I tried out hooking the cables up as per the attached, but when I turned on the red on/off switch, I heard one click noise, the fans turned on, then the fan stopped. I took the RTX4090 out of Mac Pro’s PCIE connection and tried turning on the red on/off switch again, but no luck.

Based on the link you provided for the compatibility it looked like I needed a 12 pin -> 2x8 pin Type 5 cable, and it looks like the attached photo is what I have. But no luck. Would you be able to show me some photos of how you connected those cables to your Corsair PSU and to your RTX4090???

Otherwise wondering if I need to buy this one which seems to be different in the 2x8pin holes. Mine only has 1 empty hole whereas below link has 2 empty holes.

12VHPWR 90 Degree Adapter for Corsair: PCIE 5.0 16AWG 600W 12VHPWR Adapter Dual 8 Pin PCIe to 16 Pin 12+4 Pin for RTX 4090 4080 3090TI 4070Ti Graphics Card GPU, ONLY for Corsair Power Supply (Type A)

12VHPWR 90 Degree Adapter for Corsair: PCIE 5.0 16AWG 600W 12VHPWR Adapter Dual 8 Pin PCIe to 16 Pin 12+4 Pin for RTX 4090 4080 3090TI 4070Ti Graphics Card GPU, ONLY for Corsair Power Supply

www.amazon.com

 

[Matty_TypeR]

hi, No pictures are needed, the 12 pin 4090 power lead can only connect one way to 4090, from the other end 2 X 8 pin power connectors to PSU. the psu cable which would go to the on off red switch connection and turn on. are you trying this with the 4090 installed in the 7.1 ? or card out of the mac?

use PCie lane slot 4 for the 4090, when the 4090 is installed it will call for power upon boot, and your card will work but only in windows.

if your PSU fails to turn on check continuity between switch and plug to PSU M/B connection.

I cant take pic's as my sf-750 psu is under bottom of desk fixed in position with switch. and the cable to 4090 goes up over edge of desk straight into and through pci slot and 4090 can only connect to that cable.

 

[LEOMODE]

hi, No pictures are needed, the 12 pin 4090 power lead can only connect one way to 4090, from the other end 2 X 8 pin power connectors to PSU. the psu cable which would go to the on off red switch connection and turn on. are you trying this with the 4090 installed in the 7.1 ? or card out of the mac?

use PCie lane slot 4 for the 4090, when the 4090 is installed it will call for power upon boot, and your card will work but only in windows.

if your PSU fails to turn on check continuity between switch and plug to PSU M/B connection.

I cant take pic's as my sf-750 psu is under bottom of desk fixed in position with switch. and the cable to 4090 goes up over edge of desk straight into and through pci slot and 4090 can only connect to that cable.

I tried both taking the 4090 out of mac pro, connect 12pin to 4090 and 2x8pin to corsair psu, and tried turning it on using the on/off switch. 4090 fan didn't get turned on at all. I also did this by inserting 4090 into the mac pro pcie slot and did the same thing but i cannot verify as the mac pro case enclosure blocks it from being visible, but on windows 11 device manager 4090 wasn't detected. Only 6900xt.

For your comment about psu failing to turn on, yeah not sure but i dont know what you mean by check continuity… as per above photo i attached, i did connect that to motherboard slot in the corsair psu. and i don’t think i need to buy another switch to check it out as they all looked the same. So i dont know why corsair psu fan stops after a few seconds of being turned on…

Thanks for your reply and understand your situation. Let me try to do it again (i’ve purchased the new corsair cable from amazon) and reply here again. I did put it to slot 1 for rtx4090. But i think i’m having an issue just trying to power the fan on, as the fan stops after a few seconds of turning it on with an on/off switch for some reason anyway.

 

[LEOMODE]

hi, No pictures are needed, the 12 pin 4090 power lead can only connect one way to 4090, from the other end 2 X 8 pin power connectors to PSU. the psu cable which would go to the on off red switch connection and turn on. are you trying this with the 4090 installed in the 7.1 ? or card out of the mac?

use PCie lane slot 4 for the 4090, when the 4090 is installed it will call for power upon boot, and your card will work but only in windows.

if your PSU fails to turn on check continuity between switch and plug to PSU M/B connection.

I cant take pic's as my sf-750 psu is under bottom of desk fixed in position with switch. and the cable to 4090 goes up over edge of desk straight into and through pci slot and 4090 can only connect to that cable.

Really strange, I bought the exact same PSU now which has type 4 cables instead of type 5. I also bought Corsair's type 4 cable and connected to RTX4090. I noticed that when I turn on the power of the psu, the fan runs for a second just like Corsair 850 PSU, then stops. I ordered another on/off switch in Amazon, but they all seem to be the same. So frustrated that I cannot get the fans to run until I turn it off.

Currently this one is not working

SQXBK 24-Pin Female ATX PSU Power Supply Starter On/Off Switch Jumper Bridge with Braided Cable and Red Light

Specification: Product name: 24-pin ATX power on/off Female patch cord length: 50cm / 19.69inch Wire model: 1007-18awg Interface: Standard ATX 24Pin female plug Color: red, black Features The 20/24-pin ATX/EPS power switch cable allows you to easily turn on and off the ATX power supply. The red L...

www.amazon.com

I ordered more below and will report.

CRJ 24-Pin ATX Red LED Power On/Off Switch Jumper Bridge Cable, Black Sleeved 22"

The CRJ Electronics Red LED Switch ATX Jumper allows you to conveniently turn your ATX power supply on and off. Ideal for use in many applications. Especially convenient for quickly switching your power supply on and off to pulse your water pump to eliminate water bubbles from your water cooling ...

www.amazon.com

COMeap ATX Power Jumper Cable, 24 Pin ATX Red LED Power On/Off Switch Bridge Adapter Braided 21.5-inch(55cm)

COMeap ATX Power Jumper Cable, 24 Pin ATX Red LED Power On/Off Switch Bridge Adapter Braided 21.5-inch(55cm)

www.amazon.com

 

[Matty_TypeR]

the fans only spin briefly on start up, they will not spin up until needed for cooling, it has to be under load.

 

[LEOMODE]

the fans only spin briefly on start up, they will not spin up until needed for cooling, it has to be under load.

I can confirm that I could load my RTX4090 up and running with the external PSU! So there was a lot of clarification needed from you and now I am able to run it fine. So I think I'll create a separate DIY step-by-step instruction so people like us can benefit from this.

Thanks again for your information and I hope my DIY instructions can benefit more people.

Stay tuned!