Question “Asus Prime 450M-A” does not recognize the 4th slot of memory on - AMD Ryzen 7 3700X

[Fetito]

Hello!

Help! The motherboard “Asus Prime 450M-A” does not recognize the 4th slot of memory.

I have 4x 8 GB DDR4 memory pieces of “Vengeance LPX RED” (CMK8GX4M1A2400C16R) which run at 2400 MHz. In total those are 32 GB.

However, only 3x of the 8 GB memory pieces are accepted. The BIOS does not even appear if I tried to boot with 4x pieces of RAM.

• According to what I know, the motherboard should accept up to 64 GB of RAM.
• The latest bios update has been flashed (3202, Version 3202).
• I have randomly swapped the memory pieces. They all work ok, but the system does not run if I put 4 inside. The PC only boots with 3 slots occupied. It does not matter which one. By trial and error I tried all slot.

Here is some data:

• Processor: AMD Ryzen 7 3700X 8-Core Processor (16 CPUs), ~3.6GHz
• GPU: AMD Radeon RX 5600 XT
• Motherboard: Asus Prime B450M-A
• OS: Windows 10

I attach screenshots of Thaiphoon Burner:

There is a difference in

• MEMORY MODULE: JEDEC DIMM Label, organization, Revision / Raw Card
• DRAM COMPONENTS: Manufacturer, Part Number, Composition
• FREQUENCY: Faw

Some photos:

• Motherboard:

  https://imgur.com/oY8EKik

  View: https://i.imgur.com/oY8EKik.jpg
  
• Thaipoon Burner Screenshot 1:

  https://imgur.com/0LXdqGq

  View: https://i.imgur.com/0LXdqGq.png
  
• Thaipoon Burner Screenshot 2:

  https://imgur.com/BjMq7by

  View: https://i.imgur.com/BjMq7by.png
  
• Thaipoon Burner Screenshot 3:

  https://imgur.com/uEdZrNd

  View: https://i.imgur.com/uEdZrNd.png
  

Why can I add 3 pieces, but not four, although my motherboard should accept the memory?

Thank you!

 

[NightHawkRMX]

Did you recently buy this motherboard?

 

[Fetito]

In January, I bought a new 8 GB memory stick today.

 

[NightHawkRMX]

Mixing ram is never guaranteed, and mixing ram with ICs from 2 different manufacturers just increases the risk it won't work. Chances are your ram sticks are incapable of working together.

Corsair is notorious for switching ic mfg within the same series over time.

You need a matched 4x8gb kit. Not mix and match sticks.

 

[Fetito]

I can boot up with 3 modules and mixing them, but not if I put the last one inside.

Even the packages of the memory looks the same:

https://imgur.com/G4jYYzn

View: https://imgur.com/G4jYYzn

 

[NightHawkRMX]

4 sticks is harder to run than lesser amounts. Likely 4 sticks plus mixed ram is the issue.

 

[Fetito]

Thanks.

Now it seems that one old module prevents the system to boot up. I removed all RAM modules and only the old one prevents me from booting. Could it be that one old module is broken now? (I removed all other memory pieces and just put the problematic one inside and it gets rejected). Do I have to put the problematic one into a specific slot A1, A2, B1, B2?

 

[Fetito]

Moreover, I can see that the memory sticks show different version numbers and have a different number, but the SKU seems to be the same:

https://imgur.com/jT61gO5

View: https://i.imgur.com/jT61gO5.png