add CPU 2 processer not boot

Can you share the server model. when you installing additional CPU you need to ensure that

• You have latest BIOS and iDRAC FW installed on the server
• Both CPU should be exactly same model
• Server PSU should be supported for Dual CPU config

If you have access to iDRAC can you check Lifecycle Log, SEL and POST code to see any error message regarding boot failure.

Hi,

Additionally you can run a hardware diagnostics:

https://dell.to/3m7xpuw

Steps

1. While the system is booting, press   to enter Boot Manager. Alternatively, press   to enter Lifecycle Controller.
2. Use the up and down arrow keys to select System Utilities → Hardware Diagnostics.

3. Note down the error code.

The following table describes the PSA/ePSA diagnostics error messages.

https://dell.to/2VXrJbG

Thank you

Maria Januszka

#IWork4Dell

Dell | Social Outreach Services - Enterprise

Normally it working well with 2 CPU after i add new RAM that issue happen.

When i put that CPU it can't be boot and can't log in to IDRAC 

when i put that processor to CPU 1 or CPU 2

it showing  "CPU 2 has a thermal trip (over-temperature) event."

after i removed that error processor it working well

Now i remove that processor and working with one processor

Hi Tun Myint Myat,

Could you let us know what processor model are you using for CPU1 and CPU2?

You did mentioned, it was working well with 2 CPUs until you added memory DIMM and issue appears? Can you let me know what model are the existing memories, are they Samsung M393A4K40BB0? Are you using the same memory modules to add to the server?

CPU1 and CPU2 module
Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz

Ram all are same

HMA41GR7MFR8N-TF TD AB

Hello @Tun Myint Myat,

The memory seems compatible to me. And the CPUs too, they are compatible.

I suspect there is a hardware issue. Does the CPU have any pin bended? The socket is clean and also ok? If you switch them it works well with one single processor? That will help you to discard if the problem is in the CPU itself or the socket.

Regards.

Can you share the server model. Can you try 2 CPU with only one dimm in A1 and B1 slot and try. If it is working you can add DIMM one by one in pair for both CPU and check when it is failing. 

If i switch them it not works.May be my processor have damage.

We would like to request your assistance regarding a Dell PowerEdge R760xs server with the following details:

• Service Tag:  
• Motherboard DP/N: 081KGJ
• RAID Controller: PERC H755 Front (DP/N: 03KDWX)
• Current CPU: Intel Xeon Gold 6450C

Issue Description

The server only detects CPU1. CPU2 is always reported as "Not Installed" or "Absent" in BIOS, iDRAC, and ePSA diagnostics.

Troubleshooting Performed

1. Tested multiple Intel Xeon Gold 6450C processors.
2. Swapped CPUs between CPU1 and CPU2 sockets.
3. The same CPU works normally in the CPU1 socket.
4. CPU2 socket pins appear normal with no visible bent or damaged pins.
5. BIOS and iDRAC have been reset to default settings.
6. Updated firmware and performed diagnostics.

Observations

• CPU1 is detected and operates normally.
• CPU2 is not detected under any condition.
• Memory attached to CPU2 channels is not detected.
• Lifecycle logs report CPU2-related configuration issues.
• Front PERC H755 RAID controller is also reported as not detected in some configuration checks.
• Voltage sensors for CPU2 appear present in iDRAC, but the processor itself is not recognized.

Request

Could you please help confirm:

1. Whether motherboard  fully supports dual Intel Xeon Gold 6450C processors.
2. Whether the symptoms indicate a possible CPU2 subsystem or system board failure.
3. Any additional diagnostics that can be performed to verify if the motherboard requires replacement.

We appreciate your assistance and look forward to your recommendations.

• Fully Supported: The motherboard (DP/N: 081KGJ) fully supports dual Intel Xeon Gold 6450C processors.
• Requirement: Ensure both CPUs have matching stepping/spec codes, as mismatches can halt CPU2 initialization.

• Motherboard Failure: The symptoms strongly point to a hardware failure on the motherboard's CPU2 subsystem or UPI routing lines.
• Why PERC & RAM are missing: The memory channels and the front PERC H755 rely directly on the PCIe lanes hosted by CPU2. Because CPU2 fails to initialize at the architecture level, its dependent RAM and RAID controller completely vanish from the system bus.

• Check Heatsink Torque: Ensure the CPU2 heatsink is sequentially torqued using a calibrated Torx T30 driver. Uneven pressure on LGA4677 sockets can cause pins to lose contact.
• Minimum-to-Post Test: Disconnect the front PERC, remove all expansion cards, and boot with just 1 DIMM on CPU1 (A1) and 1 DIMM on CPU2 (B1).
• Socket Inspection: Re-inspect the CPU2 socket pins under magnification for any minute debris or slightly compressed pins.

@Dell-Martin S​ but the H755 Front Cabel is stand on CPU1
take a look picture