670E Steel Legend- 4090 wont power
Printed From: ASRock.com
Category: Technical Support
Forum Name: AMD Motherboards
Forum Description: Question about ASRock AMD motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=26144
Printed Date: 27 Jul 2025 at 6:36pm
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com
Topic: 670E Steel Legend- 4090 wont power
Posted By: clok1966
Subject: 670E Steel Legend- 4090 wont power
Date Posted: 13 Jul 2023 at 5:46am
| just put my system together with all new parts, and it all works and boots, video with onboard till I put my 4090 in. Recommended Coursair HX1200 PSU, all 4 Connectors connected. I plug it in and hook power to Card and then it won't power on (still led's on board but no troubleshoot lights, the board is not starting, no fans) I unplug power with the card in, powers right up. Double-checked power connections. it's a NEW Zotech Amp Extreme. Something in BIOS I am missing?, been a long time since I built a system from scratch. did clear bios and it's updated to the current one from the Asrock website. since everything works till I put a 4090 card in I am leaning towards a bad card maybe, Just had a 3090 fail on my old rig, can I get this unlucky? (machine is on a UPS so its not some odd power issue) |
Replies:
Posted By: Xaltar
Date Posted: 13 Jul 2023 at 4:58pm
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Which 4 connectors do you have connected? The 4+4 pin connectors for CPU power? You only need one of the 8pin power connectors populated. The second is optional and is only really needed for more extreme setups with large overclocks etc. We had someone on the forums report that their system wouldn't power on with both 8pins populated so give it a shot with just 1. ------------- 
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Posted By: eccential
Date Posted: 13 Jul 2023 at 10:10pm
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I'm pretty sure that clok1966 is talking about the GPU power connector, not motherboard. I'm assuming that giant RTX 4090 is using the new 12+4 pin power connector, and you're using an adapter that takes four separate 8-pin connectors from the power supply. The new 12+4 pin connector has a bad reputation. Make sure it's REALLY REALLY IN THERE. If you have another GPU, maybe try that, if only to eliminate motherboard/CPU as culprit. |
Posted By: clok1966
Date Posted: 14 Jul 2023 at 8:26am
| yes it's the GPU, The PSU had 4 8 pins just for Vidio cards (PCI) it has 4 8 pins from PSU to the adaptor that plugs into card. What stumps me is. the card is plugged in with no Power connected the PC boots and the onboard video works fine. shut it down and connect power to video card and it won't fire up at all ( no fans nothing but the LEDS on the MB lite. |
Posted By: Rabit
Date Posted: 14 Jul 2023 at 8:42am
| Looks like dead short check with multimeter pins on adapter and later GPU. |
Posted By: Xaltar
Date Posted: 14 Jul 2023 at 8:55pm
Make sure your GPU power cables are the correct ones, 6+2 not 4+4. 4+4 is CPU power and has a completely different pinout. If you are connecting one of these it will no allow the system to power up. -------------
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clok1966 wrote:Posted By: clok1966
Date Posted: 15 Jul 2023 at 2:14am
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thanks for suggestions, I have resolved it. was a 3rd party 90 degree 4090 connector. SYBECHATF RTX 4090 4080 4070TI 3090TI 16Pin(12+4) to 4x8Pin Cable with 90 Degree 12VHPWR Connector,for Corsair Used the included STIFF connector and it all works. I should have done that right away, poor troubleshooting by me. But it was a new build and I did not want to use that horrible ugly one (pride). |
Posted By: Xaltar
Date Posted: 15 Jul 2023 at 4:02am
Happy to hear you got it sorted out  Enjoy the build  -------------
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