Question PC wont post when running dual channels

Dec 31, 2020
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Alright so, a few days ago I was taking out my stock cooler to replace with an AIO, and the CPU came out with the cooler and the pins were bent. I took it to a repair shop and they fixed it for me, though they said one pin was missing but it wouldn't be an issue as it was a reserved pin. I installed my motherboard with the CPU (i gave them both the CPU and mobo so they could test it at the shop), and when I'm putting the ram in, the pc will not boot if the ram is in any dual channel slots, 1/3, 2/4. The ram isn't the issue as I tested both sticks on their own and they work. When putting the ram in dual channel, the pc will power on with the fans spinning and all, but no display will turn on, and the lights on the motherboard doesn't turn green. XMP is enabled, tried it both enabled and disabled. Tried to do a CMOS reset.

Also when putting the ram next to each other, the pc works perfectly fine and both sticks of ram are recognized.

Specs are:

Ryzen 9 3900x
ROG Strix B550-F Motherboard
2x16GB Vengeance RGB PRO 3200MHz
 
One of the important functions of the processor pins is to manage such things as ram slots and dual channel operation.
Many times, the motherboard will operate properly without a particular pin.
The function of each pin is murky.
Sometimes a bad pin will not disable anything of importance.
It is unpredictable.
But a bad pin often seems to impact ram functions.

Did dual channel work properly before you removed the cpu?
If so, you likely caused the damage.
The missing pin may have controlled dual channel operations and it might have come out completely.
You could try to rma the processor because of the missing pin.
A pin should not come loose on a simple cpu removal.
Actually, once a processor is in the socket, it should not ever need to be removed.
To get a cooler off easily in the future, run the processor to heat it up.
That softens the paste, making the cooler easy to remove.

Since ryzen depends on fast ram for performance, you probably do not want to continue running in single channel mode.

But fixing either the cpu or motherboard is apt to be costly.
 
Dec 31, 2020
3
1
15
One of the important functions of the processor pins is to manage such things as ram slots and dual channel operation.
Many times, the motherboard will operate properly without a particular pin.
The function of each pin is murky.
Sometimes a bad pin will not disable anything of importance.
It is unpredictable.
But a bad pin often seems to impact ram functions.

Did dual channel work properly before you removed the cpu?
If so, you likely caused the damage.
The missing pin may have controlled dual channel operations and it might have come out completely.
You could try to rma the processor because of the missing pin.
A pin should not come loose on a simple cpu removal.
Actually, once a processor is in the socket, it should not ever need to be removed.
To get a cooler off easily in the future, run the processor to heat it up.
That softens the paste, making the cooler easy to remove.

Since ryzen depends on fast ram for performance, you probably do not want to continue running in single channel mode.

But fixing either the cpu or motherboard is apt to be costly.
Dual channel worked before the cpu was removed, and yeah wasn't planning on removing cpu but the thermal paste was pretty hard and it came out with the cooler (pc was running beforehand so I have no idea why the paste was hard)>
 
Jul 29, 2021
1
0
10
Hey friend. I'm facing EXACTLY the same problem that you are. (including the same cause)

The thing is, my CPU worked fine in another MB in dual channel, and another CPU worked fine on my MB with dual channel. But my CPU and my MB don't work together in dual channel.

So I don't know which part I should replace. Did you manage to find a solution?