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Question Solid red CPU light on motherboard until I restart?

Zelix

Member
Jun 30, 2018
39
2
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So I'm running into a bit of a weird issue. Whenever I cold boot my PC, the mobo displays a solid red CPU light and doesn't post (the fans are spinning and lights are on). I always fix it by hitting the restart button on my case once and it then proceeds to boot normally. It also doesn't run into any problems once booted (everything detected, no crashes, games run etc.). I have re-applied TIM to the CPU and re-set it. I have also re-set the ram, unplugged/re-plugged both the CPU 8-pin and mobo 24-pin, and reset the CMOS a couple times all to no avail. I should note that this issue only appeared once I installed my new GPU, even though I don't know how that would affect the CPU light. Could just be an extremely poor timed coincidence but might as well mention it. Any help on this is appreciated. Specs below


  • MSI B450 Gaming Pro Carbon AC (Latest Bios 7B85v1B )
  • Ryzen 5 2600x (stock clock)
  • ASUS ROG Strix RTX 2070 Super (drivers up-to-date)
  • Flare X 2x8gb 3200 cl14 (running XMP profile)
  • EVGA Supernova G3 750w
  • 860 EVO 500gb (C: Drive)


Update: RMA'd the GPU and got a replacement. Issue is still occurring so let the record show that the GPU was not the issue. I have no idea what it could be at this point.
 
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Steltek

Golden Member
Mar 29, 2001
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Since it started with the upgraded video card, I would immediately suspect the BIOS since that most recent BIOS includes stuff related to both PCIe compatibility (probably activating PCIe 4.0 compatibility, which has been problematic on some B450 boards) and decreased boot time (which may itself be causing the problem).

You might try downgrading the BIOS to 7B85v1A to see if the problem goes away. If it does, you aren't missing anything as your video card is natively PCIe 3.0 anyway.
 

Furious_Styles

Senior member
Jan 17, 2019
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Since it started with the upgraded video card, I would immediately suspect the BIOS since that most recent BIOS includes stuff related to both PCIe compatibility (probably activating PCIe 4.0 compatibility, which has been problematic on some B450 boards) and decreased boot time (which may itself be causing the problem).

You might try downgrading the BIOS to 7B85v1A to see if the problem goes away. If it does, you aren't missing anything as your video card is natively PCIe 3.0 anyway.
Agreed. Can also try re-installing old GPU and see if the same problem occurs. Then you can rule out the gpu theory.
 

Zelix

Member
Jun 30, 2018
39
2
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Were you running the current BIOS without problems prior to upgrading the video card?
Apologies for the late reply. I was running an earlier bios version prior to upgrading the gpu without any issues. Once I upgraded, I was running into POST issues which prompted me to update the bios to the latest version in the first place to see if it would fix the issue.
 

Steltek

Golden Member
Mar 29, 2001
1,917
93
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Apologies for the late reply. I was running an earlier bios version prior to upgrading the gpu without any issues. Once I upgraded, I was running into POST issues which prompted me to update the bios to the latest version in the first place to see if it would fix the issue.
By any chance, have you tried to move the new card to the second PCIe x16 slot to see if the system will POST properly?
 

Zelix

Member
Jun 30, 2018
39
2
41
By any chance, have you tried to move the new card to the second PCIe x16 slot to see if the system will POST properly?
I have not. However, if there was a problem with the slot, wouldn't have shown up with the previous gpu?
 

Steltek

Golden Member
Mar 29, 2001
1,917
93
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Not necessary. Perhaps you did something when you removed the old card.
+1.

There could also be a voltage irregularity or pin damage in the slot that the other GPU isn't sensitive to. If you had access to another system, I would also have you test it (the new card) there as well just to see if the system posted properly with the new card.

Out of curiosity, what was the specific model of your old GPU card you are replacing?
 
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Zelix

Member
Jun 30, 2018
39
2
41
+1.

There could also be a voltage irregularity or pin damage in the slot that the other GPU isn't sensitive to. If you had access to another system, I would also have you test it (the new card) there as well just to see if the system posted properly with the new card.

Out of curiosity, what was the specific model of your old GPU card you are replacing?
I had an MSI GTX 1060 Gaming X and I upgraded to an ASUS Strix RTX 2070 Super
 

Steltek

Golden Member
Mar 29, 2001
1,917
93
91
I had an MSI GTX 1060 Gaming X and I upgraded to an ASUS Strix RTX 2070 Super
If it doesn't work in the other x16 slot, were it me I would presume that the video card is bad and try a swap. I mean, it could still be a bad motherboard, a BIOS timing issue during POST, or even a flaky power supply (since the new card requires more power than the old one did). However, the system works with your old card just fine. It initially wouldn't post with the new card, and only posted after a BIOS upgrade and even then only if you hit reset. It is possible the card could have an intermittent failure, or that it is unstable with the factory overclock. The only other thing you could try to be sure is to attempt to boot it on a different machine.

One final thing you can try - if your system has MSI's version of fast boot enabled in the BIOS, try to disable it followed by reinstallation of the new card.
 
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Zelix

Member
Jun 30, 2018
39
2
41
If it doesn't work in the other x16 slot, were it me I would presume that the video card is bad and try a swap. I mean, it could still be a bad motherboard, a BIOS timing issue during POST, or even a flaky power supply (since the new card requires more power than the old one did). However, the system works with your old card just fine. It initially wouldn't post with the new card, and only posted after a BIOS upgrade and even then only if you hit reset. It is possible the card could have an intermittent failure, or that it is unstable with the factory overclock. The only other thing you could try to be sure is to attempt to boot it on a different machine.

One final thing you can try - if your system has MSI's version of fast boot enabled in the BIOS, try to disable it followed by reinstallation of the new card.
Yeah at this point I am probably just gonna try and RMA the card as I am still within my return period with Newegg.
 
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Micrornd

Senior member
Mar 2, 2013
963
84
91
I haven't seen anyone ask, so I will -

Do you have both 8pin power connectors on the 2070 super plugged in?
Do you have both the 8pin AND the 4pin power connectors on the motherboard plugged in?
 

Zelix

Member
Jun 30, 2018
39
2
41
I haven't seen anyone ask, so I will -

Do you have both 8pin power connectors on the 2070 super plugged in?
Do you have both the 8pin AND the 4pin power connectors on the motherboard plugged in?
Both 8-Pins are plugged into the gpu. I wondered about the additional cpu 4-pin so I googled it and everywhere said that the additional CPU 4-pin is only for extreme overclocking and is unnecessary.
 

Micrornd

Senior member
Mar 2, 2013
963
84
91
I wondered about the additional cpu 4-pin so I googled it and everywhere said that the additional CPU 4-pin is only for extreme overclocking and is unnecessary.
You may want to look at the manual that came with the board.
MSI indicates it should be plugged in and doesn't make any such distinctions.
 

Zelix

Member
Jun 30, 2018
39
2
41
You may want to look at the manual that came with the board.
MSI indicates it should be plugged in and doesn't make any such distinctions.
I can't find anything in the manual that would tell me otherwise. I've been running only the 8-pin all this time with no issues so I assumed it wasn't needed.
 

Markfw

CPU Moderator, VC&G Moderator, Elite Member
Super Moderator
May 16, 2002
19,464
6,873
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That motherboard has 2 CPU plugs, and 8 pin and a 4 pin. Are they both plugged in ?
 

Markfw

CPU Moderator, VC&G Moderator, Elite Member
Super Moderator
May 16, 2002
19,464
6,873
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MSI told that only the 8 pin is required and that the additional 4 pin is only for extreme overclocking
Many people on the CPU forum can't even post without both plugged in. Since you went to a video card that draws more power, its possible that is your problem. Try it, your power supply has 2 CPU plugs, its won't cost anything to plug it in.

MSI could be wrong, their tech support person is not an engineer.
 

Zelix

Member
Jun 30, 2018
39
2
41
Many people on the CPU forum can't even post without both plugged in. Since you went to a video card that draws more power, its possible that is your problem. Try it, your power supply has 2 CPU plugs, its won't cost anything to plug it in.

MSI could be wrong, their tech support person is not an engineer.
Just tried it. No dice. I think I've exhausted all solutions by now. Not sure what it could be. Could be the motherboard but I'm not sure.
 

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