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Second Xeon not seen by motherboard

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June 26, 2012 12:22:17 AM

Hi,

I have a SuperMicro X7DBR-E motherboard with two identical xeon quad-core cpu (step code same), but the motherboard is only seeing one of the CPU's. I have tried re-seating several times, swapping the two cpu, and reflashing the BIOS to no avail. Does anyone have any ideas or is my motherboard trashed?

Thanks.

More about : xeon motherboard

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June 26, 2012 1:03:41 AM

Are the Xeon CPUs DP/MP models? If they are only cheap UP models then they are not multiprocessor capable.
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a b V Motherboard
June 26, 2012 1:14:09 AM

A few possibilities come to mind.
1). Power supply. Are all of the motherboard power connections (24 + 8 + 4 pin)populated and is the power supply heavy enough (500W) for the motherboard?
2). Failed CPU. Have you tried each cpu alone in each socket?
3). Bent socket pins. Have you checked to see if all the pins line up in both directions on the socket? The previous test should identify if a socket is faulty.
4). If it's second hand this is possiby why it has been dumped.
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a b à CPUs
June 26, 2012 3:05:29 AM

A silly idea here....but i hope ur not running Windows7 home edition or something :)  Multi-CPU configs are only supported by W7 Ultimate IIRC :) 
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a b V Motherboard
June 26, 2012 4:28:04 AM

egagdesigns said:
Hi,

I have a SuperMicro X7DBR-E motherboard with two identical xeon quad-core cpu (step code same), but the motherboard is only seeing one of the CPU's. I have tried re-seating several times, swapping the two cpu, and reflashing the BIOS to no avail. Does anyone have any ideas or is my motherboard trashed?

Thanks.


Where do you see only one CPU being detected- in the BIOS or on the POST screen or in the OS? If you see both CPUs being detected in the BIOS or on the POST screen but only one in the OS, then your OS either does not support multiple CPU sockets (any home version of Windows) or not set up properly for more than four CPU cores (if you rolled your own *nix kernel and set NR_CPUS.) Go into the BIOS and see what it says about what CPUs it sees. If you see both CPUs in the BIOS but only one in Windows, get yourself a suitable version of Windows.

If you only see one CPU in the BIOS, then the fact that you have swapped the CPUs and each one works properly when in the first socket means the CPUs are good. I'd bet one of the following being the cause of the second CPU not showing up:

1. Second CPU turned off in the BIOS. Go and turn it back on and it should show up. I actually doubt this is the case if you reflashed the BIOS, most boards default to having all CPUs turned on.
2. Defective socket/bent socket pins for the second CPU
3. Bad contact between the CPU and socket for the second CPU
4. Not having both the 8 pin and 4 pin power connectors plugged in
5. Defective power supply not supplying power to both the 8 pin and 4 pin connectors

Pinhedd said:
Are the Xeon CPUs DP/MP models? If they are only cheap UP models then they are not multiprocessor capable.


The board is an LGA771 board and there were only two UP-only models made for LGA771, and they were rare- a single core ULV unit and one dual-core. Any quad core LGA771 unit is going to support DP operation.
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June 26, 2012 4:52:50 AM

MU_Engineer said:
Where do you see only one CPU being detected- in the BIOS or on the POST screen or in the OS? If you see both CPUs being detected in the BIOS or on the POST screen but only one in the OS, then your OS either does not support multiple CPU sockets (any home version of Windows) or not set up properly for more than four CPU cores (if you rolled your own *nix kernel and set NR_CPUS.) Go into the BIOS and see what it says about what CPUs it sees. If you see both CPUs in the BIOS but only one in Windows, get yourself a suitable version of Windows.

If you only see one CPU in the BIOS, then the fact that you have swapped the CPUs and each one works properly when in the first socket means the CPUs are good. I'd bet one of the following being the cause of the second CPU not showing up:

1. Second CPU turned off in the BIOS. Go and turn it back on and it should show up. I actually doubt this is the case if you reflashed the BIOS, most boards default to having all CPUs turned on.
2. Defective socket/bent socket pins for the second CPU
3. Bad contact between the CPU and socket for the second CPU
4. Not having both the 8 pin and 4 pin power connectors plugged in
5. Defective power supply not supplying power to both the 8 pin and 4 pin connectors



The board is an LGA771 board and there were only two UP-only models made for LGA771, and they were rare- a single core ULV unit and one dual-core. Any quad core LGA771 unit is going to support DP operation.


There are actually a couple of OEM LGA771 quads which are only single socket capable (Yorkfield-CL X3323/X3353/X3363) in addition to the Wolfdale-CL that you mentioned . I doubt that they would be found in a Supermicro motherboard since those are usually found in retail and whitebox servers.
June 26, 2012 10:45:09 AM

pauls3743 said:
A few possibilities come to mind.
1). Power supply. Are all of the motherboard power connections (24 + 8 + 4 pin)populated and is the power supply heavy enough (500W) for the motherboard?
2). Failed CPU. Have you tried each cpu alone in each socket?
3). Bent socket pins. Have you checked to see if all the pins line up in both directions on the socket? The previous test should identify if a socket is faulty.
4). If it's second hand this is possiby why it has been dumped.


1) All the motherboard's power connections are populated and have been reseated to verify that's not the problem. I suppose I could also take a meter and measure them too to verify voltage. Also, it's a 560Watt power supply.

2) I took out the cpu in one socket and the motherboard booted up fine off the single processor, so I took that same processor to the other socket and it would not boot up, leading me to believe it's the socket.

3) I have examined the pins very closely and I see no damage at all.

June 26, 2012 10:47:52 AM

MU_Engineer said:
Where do you see only one CPU being detected- in the BIOS or on the POST screen or in the OS? If you see both CPUs being detected in the BIOS or on the POST screen but only one in the OS, then your OS either does not support multiple CPU sockets (any home version of Windows) or not set up properly for more than four CPU cores (if you rolled your own *nix kernel and set NR_CPUS.) Go into the BIOS and see what it says about what CPUs it sees. If you see both CPUs in the BIOS but only one in Windows, get yourself a suitable version of Windows.

If you only see one CPU in the BIOS, then the fact that you have swapped the CPUs and each one works properly when in the first socket means the CPUs are good. I'd bet one of the following being the cause of the second CPU not showing up:

1. Second CPU turned off in the BIOS. Go and turn it back on and it should show up. I actually doubt this is the case if you reflashed the BIOS, most boards default to having all CPUs turned on.
2. Defective socket/bent socket pins for the second CPU
3. Bad contact between the CPU and socket for the second CPU
4. Not having both the 8 pin and 4 pin power connectors plugged in
5. Defective power supply not supplying power to both the 8 pin and 4 pin connectors



The board is an LGA771 board and there were only two UP-only models made for LGA771, and they were rare- a single core ULV unit and one dual-core. Any quad core LGA771 unit is going to support DP operation.



It's in the POST screen where I only see 1 of 1 processors with 4 logical cores. BIOS on this board isn't that helpful in diagnosing the issue. If it helps any, it shows that it isn't getting a temperature reading for CPU2, which is the socket in question.

What should the voltages be @ the 8pin and 4pin connectors so I can check it? Should be twelve volts from yellow to black, right?
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a b V Motherboard
June 27, 2012 5:22:03 AM

egagdesigns said:
It's in the POST screen where I only see 1 of 1 processors with 4 logical cores. BIOS on this board isn't that helpful in diagnosing the issue. If it helps any, it shows that it isn't getting a temperature reading for CPU2, which is the socket in question.

What should the voltages be @ the 8pin and 4pin connectors so I can check it? Should be twelve volts from yellow to black, right?


Hmm, sounds like the socket may be defective. Voltage in the connectors should be 12 volts from yellow to black.
July 2, 2012 7:59:42 AM

MU_Engineer said:
Hmm, sounds like the socket may be defective. Voltage in the connectors should be 12 volts from yellow to black.



Insert Xeon only on the second slot. Leave CPU_1 slot empty. Remove all FBDIMMs. Power on the machine. Listen if you can hear beeps. If it beeps, then its good sign. The slot is good.

Populate only one FBDIMM with both procs on both CPU slots and see if the server boots. Ensure the 5v has atleast 3amps on them. Remove all power to HDD and Optical drives. Post your reply. We will see.

Regards
Sinu Chacko
!