Der bleibt neuerdings einfach stehen! :-(

Interval Since Last Panic Report:  19838364 sec
Panics Since Last Report:          11
Anonymous UUID:                    C3CD0FDC-65A9-417F-AEA3-C13858F956AB

Wed Apr 24 13:24:37 2013
Machine-check capabilities (cpu 4) 0x0000000000001c09:
 family: 6 model: 26 stepping: 5 microcode: 17
 Intel(R) Xeon(R) CPU           E5520  @ 2.27GHz
 9 error-reporting banks
 threshold-based error status present
 extended corrected memory error handling present
Machine-check status 0x0000000000000004:
 machine-check in progress
MCA error-reporting registers:
 IA32_MC0_STATUS(0x401): 0x0000000000000800 invalid
 IA32_MC1_STATUS(0x405): 0x0000000000000800 invalid
 IA32_MC2_STATUS(0x409): 0x0000000000000000 invalid
 IA32_MC3_STATUS(0x40d): 0x0000000000000000 invalid
 IA32_MC4_STATUS(0x411): 0x0000000000000000 invalid
 IA32_MC5_STATUS(0x415): 0x0000000000000000 invalid
 IA32_MC6_STATUS(0x419): 0x0000000000000000 invalid
 IA32_MC7_STATUS(0x41d): 0x0000000000000000 invalid
 Package 0 logged:
 IA32_MC8_STATUS(0x421): 0x0000000000000000 invalid
 Package 1 logged:
 IA32_MC8_STATUS(0x421): 0x0000000000000000 invalid
panic(cpu 4 caller 0x2aaf41): Machine Check at 0x012c3893, thread:0x2e46fb7c, trapno:0x12, err:0x0,registers:
CR0: 0x8001003b, CR2: 0x70746fc0, CR3: 0x00100000, CR4: 0x00000660
EAX: 0x00000020, EBX: 0x012d62d0, ECX: 0x00000001, EDX: 0x012d5940
ESP: 0xa66cbbc0, EBP: 0xa66cbc18, ESI: 0x00000000, EDI: 0x2a1e4000
EFL: 0x00000002, EIP: 0x012c3893

Backtrace (CPU 4), Frame : Return Address (4 potential args on stack)
0x99177fb8 : 0x21b837 (0x5dd7fc 0x99177fec 0x223ce1 0x0) 
0x99178008 : 0x2aaf41 (0x59dfe4 0x59e0d1 0x12c3893 0x2e46fb7c) 
0x991780f8 : 0x2a29f2 (0x1 0x3e223436 0x31327830 0x2f3c6364) 
0xa66cbc18 : 0x12baee7 (0x9908d0a8 0x6 0x2a1e4000 0x0) 
0xa66cbcf8 : 0x12bc850 (0xffffffff 0x7fffffff 0x0 0x0) 
0xa66cbdf8 : 0x2ad0c5 (0xffffffff 0x7fffffff 0xa66cbe38 0x99096000) 
0xa66cbe18 : 0x225bba (0x9909649c 0x9f059507 0xa7 0x99096488) 
0xa66cbe78 : 0x22698c (0x1 0x2e46fb7c 0x2a21e0dc 0x210bc1) 
0xa66cbee8 : 0x2275b0 (0x2e46fb98 0x0 0x0 0x506ad1) 
0xa66cbf58 : 0x227631 (0x23014c 0x863ea0 0x0 0x2a45c9) 
0xa66cbf78 : 0x2302e6 (0x23014c 0x863ea0 0x0 0x0) 
0xa66cbfc8 : 0x2a179c (0x863ea0 0x0 0x10 0x2d729684) 
      Kernel Extensions in backtrace (with dependencies):
         com.apple.driver.AppleIntelCPUPowerManagement(142.6.0)@0x12b9000->0x12dcfff

BSD process name corresponding to current thread: kernel_task

Mac OS version:
10K549

Kernel version:
Darwin Kernel Version 10.8.0: Tue Jun  7 16:33:36 PDT 2011; root:xnu-1504.15.3~1/RELEASE_I386
System model name: MacPro4,1 (Mac-F221BEC8)