Question MSI B450-A PRO MAX & Ryzen 3700x CPU not detected

Oct 19, 2020
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So I've been putting together my first new build with the following specs:

Motherboard: MSI B450-A Pro Max
CPU: Ryzen 7 3700x
GPU: EVGA GeForce GTX 1080
RAM: Corsair Vengeance LPX 16GB
Power Supply: Cooler Master - MWE Gold 750W ATX12V 2.31 80 Plus Gold Modular

Everything is powering on, but the machine won't post and the debug light for CPU is lit up to indicate that the CPU isn't being detected or is failing.

Things that I have tried:
  • Resetting CMOS with JBAT1
  • Flashing BIOS
  • Flashing BIOS with the prior version of BIOS (7B86vM6)
  • Remounting the CPU - Booting with 1 stick of RAM in A2 slot
  • My original RAM with 3200 MHZ was not listed on the compatibility list so I tried it with 1 stick of 3000 MHZ and 2400 MHZ with neither working.
I just checked the compatibility list for my specific CPU Code (100-100000071) and it does not appear on the list. On the list, the 3700x's CPU Code is (100-000000071). There is only one different number in the code, but could that cause a compatibility issue here? This is my first time building, so I don't know if something as little as that could be the problem.

Other than that, I can't figure out what else I can try here. It seems like it's a problem with the CPU, but there could also be something going on with the motherboard. I've already had to RMA the motherboard once and they sent me a new one. I'm considering ordering a very cheap CPU to test with and if it turns out the 3700x is a dud, then I'll get it replaced with the warranty.

Hoping someone out there has encountered something similar and has some advice or a solution to determine which part is the problem.
 
Last edited:

BogdanH

Proper
Sep 21, 2020
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About CPU code:
100-00xxx -sold as tray/OEM
100-10xxx -sold boxed (with cooler)
-other than that, CPU itself is the same.

I have no idea why CPU isn't recognized by your mobo. I knowis a stupid question, but.. you did connect power to CPU_PWR1 header (top-left on mobo), right?
 
Oct 19, 2020
10
2
15
0
About CPU code:
100-00xxx -sold as tray/OEM
100-10xxx -sold boxed (with cooler)
-other than that, CPU itself is the same.

I have no idea why CPU isn't recognized by your mobo. I knowis a stupid question, but.. you did connect power to CPU_PWR1 header (top-left on mobo), right?
Ah gotcha, then that's probably not the issue. Yeah, I do have the correct CPU 8pin connector plugged into CPU_PWR1 in the top left.
 
...
I just checked the compatibility list for my specific CPU Code (100-100000071) and it does not appear on the list. On the list, the 3700x's CPU Code is (100-000000071). There is only one different number in the code, but could that cause a compatibility issue here? This is my first time building, so I don't know if something as little as that could be the problem.
....
It might not be significant...or then again it might.

Where did you purchase the CPU? did you get it in a box, with a cooler and sealed? was it just the CPU, maybe in a clamshell package?

The concern is that it could be what's called a tray CPU. Those are CPU's sold in trays, usually to system integrators (like CyberPower) to put in their systems. They're good CPU's when sold but they will get a lot more handling, often getting repackaged multiple times before being sent on to a customer as a discrete CPU. And handling introduces the possibility of damage....usually through something like ESD.

Even if it came in a box, if the retailer is sketch it could be a forged box and seal and even heatsink.

The other issue is they are warrantied by AMD to the original purchaser, not the end customer. You're expected to go back to the system integrator for relief...that would be the retailer if it is a tray CPU.
 
Oct 19, 2020
10
2
15
0
It might not be significant...or then again it might.

Where did you purchase the CPU? did you get it in a box, with a cooler and sealed? was it just the CPU, maybe in a clamshell package?

The concern is that it could be what's called a tray CPU. Those are CPU's sold in trays, usually to system integrators (like CyberPower) to put in their systems. They're good CPU's when sold but they will get a lot more handling, often getting repackaged multiple times before being sent on to a customer as a discrete CPU. And handling introduces the possibility of damage....usually through something like ESD.

Even if it came in a box, if the retailer is sketch it could be a forged box and seal and even heatsink.

The other issue is they are warrantied by AMD to the original purchaser, not the end customer. You're expected to go back to the system integrator for relief...that would be the retailer if it is a tray CPU.
I don't think that is the issue, I bought it brand new from Newegg
 
I don't think that is the issue, I bought it brand new from Newegg
Newegg is a reputable e-tailer...but they also front for other vendors who might re-sell OEM tray products. There's nothing illegal about that and they are brand new, it's just a kind of buyer beware sort of thing. And the extra handling a tray part gets that makes it more likely it could be defective since boxed CPU's are extremely rarely defective .

If it's the CPU that is defective you won't get a warranty return from AMD if it's an OEM tray part, so that makes it an issue. Hopefully you can from Newegg though.
 
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Oct 19, 2020
10
2
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Newegg is a reputable e-tailer...but they also front for other vendors who might re-sell OEM tray products. There's nothing illegal about that and they are brand new, it's just a kind of buyer beware sort of thing. And the extra handling a tray part gets that makes it more likely it could be defective since boxed CPU's are extremely rarely defective .

If it's the CPU that is defective you won't get a warranty return from AMD if it's an OEM tray part, so that makes it an issue. Hopefully you can from Newegg though.
I took a look and don't think that it was an OEM tray part, but I'm not 100% sure.
https://www.newegg.com/amd-ryzen-7-3700x/p/N82E16819113567?Item=N82E16819113567

It's unfortunately been past the 30 return window so I'm not going to be able to get help from Newegg. On the product page, it does say it has 3 year warranty so I'm going to get in touch with AMD.
 
Oct 19, 2020
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I just reset CMOS with JBAT1 and flashing BIOS again and noticed that the CPU light was still lit up on the motherboard. The only things that were plugged into the motherboard were the CPU_PWR1 and ATR_PWR1, so it makes sense that the CPU wouldn't be detected. What doesn't make sense to me is why the VGA and DRAM lights aren't lighting up either since the GPU and RAM aren't plugged in. Could this indicate that the problem is with the motherboard itself, not the CPU?
 
I took a look and don't think that it was an OEM tray part, but I'm not 100% sure.
https://www.newegg.com/amd-ryzen-7-3700x/p/N82E16819113567?Item=N82E16819113567
....
The part no in the ad is :
100-100000071BOX

which would make it a BOX part. I'm not one to think Newegg would deal in counterfeit or relabeled parts nor false advertising. So I think you're OK there.

I think the POST process stops at the point where it fails and lights the appropriate light. CPU is the first thing to initialize so it would be the first to fail.

Your best recourse is with an AMD RMA, if it is indeed the CPU that's defective. It would be nice to have another one to try in the motherboard to be sure. But also be sure to try MSI tech support to see if they have suggestions. One thing I can think of is doing the CMOS reset with the battery pulled out and power cord disconnected. Leave it shorted for several minutes...maybe an hour or more... before reassembling.
 
Last edited:
Oct 19, 2020
10
2
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The part no in the ad is :
100-100000071BOX

which would make it a BOX part. I'm not one to think Newegg would deal in counterfeit or relabeled parts nor false advertising. So I think you're OK there.

I think the POST process stops at the point where it fails and lights the appropriate light. CPU is the first thing to initialize so it would be the first to fail.

Your best recourse is with an AMD RMA, if it is indeed the CPU that's defective. It would be nice to have another one to try in the motherboard to be sure. But also be sure to try MSI tech support to see if they have suggestions. One thing I can think of is doing the CMOS reset with the battery pulled out and power cord disconnected. Leave it shorted for several minutes...maybe an hour or more... before reassembling.
Yeah I agree, I'm going to get in contact with them and hopefully can get a replacement without too much hassle. I've been in contact with MSI and have tried everything they suggested, as well as RMA'd the original motherboard that I purchased.
 
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