What to do if the PSU hasn't got enough MOLEX

hi guys,

I would kindly like to ask you, I have EVGA SuperNOVA 1600 P2 Power Supply.
It has 8 GPU cable, but it comes with 5 MOLEX connectors only. The problem is, I want to feed 7 risers.
The riser comes with a SATA to MOLEX cable. They have good build quality, so they should not begin to burn…
I tried it… and it works only sometimes. After reboot the gpu disapperas, after another reboot, it comes again… etc.
I connected it directly to the cable coming from the PSU. Anyone experienced something similar?
Is there any other way ?

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FYI, you can buy v7 risers with sata power now.. So if you buy some molex powered risers and some sata powered risers, then you dont have to use thse cheap sata->molex converters they come with.

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Are you sure this is a power issue as yes whilst molex is preferred over these sata to molex cables it shouldn't prevent it working.

What's the rest of your build and specifically your motherboard? Also it's definitely not uncommon for a riser to be broken. Have you confirmed each work individually?

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The sata->molex cables have worked well for me. I'm using some now on GTX 1050 Ti which don't have 6+2 plugs (they are purely PCI-e slot powered) and they work fine. Potential fire hazard? Maybe, but I check them often and they don't even get warm to the touch so unless they are defective to begin with they seem to be able to handle 75 watts no problem.

In my experience this is rarely a PSU issue and is more likely an OS or gpu driver related issue--could also be motherboard itself, you'll have to check all your settings in the BIOS, check the motherboard specs and confirm it can handle 7 GPUs, etc.

I'm having a similar problem right now on several HP Z400 desktops (don't ask, seemed like a good idea at the time) that only have four PCI-e slots on the motherboard. They work fine for days, then when rebooted they come back with only some of the cards detected. I have to do this thing where I wiggle the PCIe cables or swap the risers around to different slots and all is well again... a few days later the same issue with some cards not detected---seems to happen more with Windows 7, the ones running Windows 10 are not as fussy. I have the same version 5 risers as in your picture. I even upgraded to version 6 risers but didn't make any difference. I hope you figure out your issue!

Thank you guys very much for the tipps. I will definitely try those SATA risers as well.
What a pity, that EVGA comes with 5 MOLEX only.

Well after all, I managed to get it working, it is a sapphire rx 480 nitro+ oc, and the cable isn't getting hot at all. Maybe also, because the GPU has 8pin power and the current is used only to power the riser. But anyways, I am a bit afraid, because 75 W what could be taken by molex vs SATA with <50W is much more...

Use these 6-pin VGA connectors along with MOLEX: http://www.ebay.com/itm/131996650201?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Risers are fun to collect anyways!

As long as you do not overclock, the RX 470/RX 480's are safe to use with the molex to sata power connector on the risers. You have a modular PSU though, so you can also get additional molex cables and not use the Sata cables at all.

For those worried about molex to sata cables, check out this video.

Thanks for video, it convinced me not to use sata to molex adapters, because I have exactly those ones which should not be safe to use.

Anyway... I already burned one PSU 1300w because I use it for run 2x290 and 4x290x and after few weeks of running it burned connector from PSU - mobo slot. I used ribbon risers with molex but I didn't plug molex in.

After that I bought 1100w chieftec and 750w psu and connected 2 ribbon risers to molex (from one mobo slot) and another 4 ribbon risers without molex and it worked fine for few months (it still run fine), also checked cables once per week and they are perfect and cold.

But... I decided to buy usb - molex powered risers but I didn't know that they will not work if they are not connected to molex too (ribbon ones works without molex supply).
I have 4 molex connectors on one cable from psu and a lot of sata connectors.

So the question is :blush:
Should I use 4 usb molex riser connected to one cable and 2 ribbons.
Or 2 usb molex risers and 4 ribbon.

Thanks for your advices :slight_smile:

No advices :)? 20char

mold molex worked for me for over a year with only 1 cable burned in the entire farm ... no damange except the cable ... but their os a hgher risk plus we use open frames which cools the cabls too