PC Processors

[Similisora]

Hello,

I recently received a new CPU (AMD Ryzen 5700x3D) but I can't start my PC with it, it is stuck on the CPU red light on my motherboard. I litterally tried everything I found on Internet (reddit, MSI, AMD, etc.) but nothing worked for me.

Before this, I had an ADM Ryzen 3600 and everythings was working fine. If I put it back, this is ok.

There is my setup :​

• Motherboard : B450 GAMING PRO CARBON MAX WIFI
• CPU (old -> new) : AMD Ryzen 5 3600 -> AMD Ryzen 7 5700x3D
• GPU : GeForce RTX™ 2060 GAMING Z 6G
• RAM : Corsair VENGEANCELPX16GB (2 x 8 Go) DDR4 3600 (Pc4-28800) C181.35V
• PSU : Seasonic Core GM - 650W (80 + Gold)
• SSD 1 (OS) : Samsung 970 EVO Plus
• SSD 2 (Data) : Samsung SSD 860

What I have already tried :​

MOBO side :

• I flashed the bios to the version recommanded on the official MSI support site (7B85v2E). Then I tried the latest beta version (7B85v2G1). Same thing, still stuck with CPU red light.
• I checked if CPU was really ok for my B450 mobo, and yes : https://fr.msi.com/Motherboard/B450-GAMING-PRO-CARBON-MAX-WIFI/support#cpu
• I cleared the CMOS : first I use the jumper (shorting the two pins with a screwdriver), then I removed the battery (>15 min) and press power button to drain all remaining electricity).

CPU side :

• There is no pin bent on the CPU. A tech store near from my house tested it on an other mobo and they confirm me that it's working. So it's not an issue about the CPU.
• I bought an AMD Ryzen 5700x (not 3D) and everything works with it.
• I tried to wait 5min while booting but still stuck on CPU red light.

Memory side :

• I tried to boot with only one RAM : same issue. I tried the 4 slots.
• I removed the 2 RAM : the red light goes to DRAM. So CPU seems POST. But as I said, the CPU is working on another mobo.
• I checked the RAM compatibility and it seems OK (DDR4 3600). The tech in the store tried with another RAM and still won't boot.

PSU side :

• I checked the PSU connected to the 8 CPU PWR pins : all seems fine. I don't think I need the last 4 for a 105W CPU.

So it seems to be an issue with the BIOS, as the 5700x works but the 3D does not (new 5000 series). On the MSI support page, the 5700x doesn't need the same recent update.
But my BIOS is up to date so I don't understand (I checked the version on BIOS and Windows 11).

Guys I'm really lost, I don't know what to do anymore but since this should work, I don't want to give up now.

Do you have any idea ?

[FunkZ]

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@Similisora wrote:

• I checked the PSU connected to the 8 CPU PWR pins : all seems fine. I don't think I need the last 4 for a 105W CPU.

So it seems to be an issue with the BIOS, as the 5700x works but the 3D does not (new 5000 series). 

---

If I am reading that correctly, you only have a 4pin connector plugged into the motherboard CPU power?

Where do you have it connected? Half of the 8pin CPU_PWR1 or the 4pin CPU_PWR2? Have you tried the other position?

The manual doesn't state which should be used. (page 35)

https://download-2.msi.com/archive/mnu_exe/mb/E7B85v1.4.pdf

The 5700X is a 65W TDP processor, as is the 3600. The 5700X3D is a 105W TDP / 142W PPT processor. It requires more power.

You're correct that theoretically a 4pin should be able to provide up to 192W of power, however MSI BIOS may be halting POST because it doesn't see required CPU power connector. If switching the power connector position doesn't work, open an MSI support ticket to have them confirm.

[Similisora]

No, I probably expressed myself badly, sorry (French). I wanted to say that I have the 8 pins connected (CPU_PWR1). So all seems good at this point.

There are 4 free (CPU_PWR2) out of the 12 total. But from what I've read I don't need it.

[Similisora]

Yes I opened a ticket friday to MSI but still no response. So I continue my troubleshooting...

[Similisora]

Maybe the 3D V-Cache need something more ? I tried to update the AMD chipset driver (never done before) to the version 6.10.17.152, but still the same issue.

Am I missing something ? I see many topics where people just update the BIOS and that's over, this is working on B450. It's driving me crazy.

[Dullifor]

The exact same thing is happening to me, but on an MSI B450 Gaming Plus Max.

Swapped back to 3600 and everything is fine, but can't manage to make the 5700x3d work, it does not even beep.

Sorry that I can't be of use.

[Similisora]

Oh so what did you do ? Give up ? I hesitate to downgrade to 5700x.
Or upgrade to mobo AM5 with 9800X3D but it not ne same price

[Dullifor]

So far I have just made sure everything on the Motherboard is plugged correctly to the PSU, and tried again after updating the BIOS drivers to no success. Then I found your post and here I am. Hopefully we find a fix...

[Similisora]

Yes I hope too. If I can help you with all I learned :

- Try with the 4 BIOS versions (7B86vHK, 7B86vHL, 7B86vHM1, 7B86vHN2). Then are you sure your flash worked ? The right version is displayed on your BIOS ?

- Try to clear CMOS before flashing the BIOS

- Try to update your chipset drivers (https://www.amd.com/en/support/downloads/drivers.html/chipsets/am4/b450.html)

- Try with only one RAM

- Did you try the CPU on another mobo ? To exclude a DoA

- Are you sure there is no pin bent on the 5700X3D ?

On my side, I oppened a ticket to MSI support.

And even if my CPU was tested on another mobo, I just can't believe it really worked (because I literally test everything except this) so I ordered a new one which will arrive in a few days.

I'll keep you up to date.

Good luck !