BSOD with cores 3 or 4

Hi,
I need some advice.

Built new PC using ASUS M479XTD AVO and Phenom 944 X4, only 1 Gb of DDR3 and a Radeon HD 4670, PSU is Artic 500.
After some initial problems trying to install XP, I gave up and bought Windows 7 Pro 32 bit.
This was a clean install which was completed without any problems - but only 1 core was enabled as I had not enabled any of the other cores (think this is the default value for this MB)

With the 2nd core enabled still no problems. But as soon as I tried cores 3 or 4 I get BSOD, either prior to the logon screen, or occasionally once the log on screen is waiting for the password.

Downloaded and flashed latest BIOS for MB - Fault still apparent
Downloaded and installed latest Driver for Graphics card - Fault still apparent.

If I try any combination of using either core 3 and/or core 4 then its a guaranteed BSOD.

Ran Mem Test for 100 passes - no problems reported.
2 questions would seem sensible

Whats the chance of a processor with 2 duff cores - seems real unlikely.

Do cores 3 and 4 work at all differently to core 2? If so how.

Or
Have I missed something real obvious? Thats a third question

[ATTACH]117024

Hello and Welcome !

Seems like some Hardware component is causing the System to crash. Run a complete hardware diagnostic follow this article Hardware Diagnostic !! « Captain Debugger follow this article Stop 0x124 - what it means and what to try

Code:

WHEA_UNCORRECTABLE_ERROR (124)
A fatal hardware error has occurred. Parameter 1 identifies the type of error
source that reported the error. Parameter 2 holds the address of the
WHEA_ERROR_RECORD structure that describes the error conditon.
Arguments:
Arg1: 00000000, Machine Check Exception
Arg2: 851e1024, Address of the WHEA_ERROR_RECORD structure.
Arg3: b41a2000, High order 32-bits of the MCi_STATUS value.
Arg4: 28000145, Low order 32-bits of the MCi_STATUS value.

Debugging Details:
------------------


BUGCHECK_STR:  0x124_AuthenticAMD

CUSTOMER_CRASH_COUNT:  1

DEFAULT_BUCKET_ID:  VISTA_DRIVER_FAULT

PROCESS_NAME:  explorer.exe

CURRENT_IRQL:  1f

STACK_TEXT:  
82b3fd2c 82e3af3f 00000124 00000000 851e1024 nt!KeBugCheckEx+0x1e
82b3fd68 82aeaf04 851b6869 851e1024 82a844d0 hal!HalBugCheckSystem+0xab
82b3fd98 82e3b1f1 851e1ea8 82e48e40 00000000 nt!WheaReportHwError+0x230
82b3feac 82e3b2e3 851e1ea8 851e1ef8 00000000 hal!HalpMcaReportError+0x3b
82b3fed0 82e3b54f 00000000 851e1ef8 82b3fff0 hal!HalpMceHandler+0x8b
82b3fee0 82e315f5 00000000 00000000 00000000 hal!HalpHandleMachineCheck+0x3b
82b3fff0 82e2e261 00000000 801dc000 00000000 hal!HalpMcaExceptionHandler+0x87
82b3fff0 00000000 00000000 801dc000 00000000 hal!HalpMcaExceptionHandlerWrapper+0x89


STACK_COMMAND:  kb

FOLLOWUP_NAME:  MachineOwner

MODULE_NAME: hardware

IMAGE_NAME:  hardware

DEBUG_FLR_IMAGE_TIMESTAMP:  0

FAILURE_BUCKET_ID:  0x124_AuthenticAMD_PROCESSOR_CACHE

BUCKET_ID:  0x124_AuthenticAMD_PROCESSOR_CACHE

Followup: MachineOwner