unerwartetes Herunterfahren/Einfrieren

Hallo zusammen,

ich besitze einen Mac Pro (Late 2008) und habe seit kurzem folgendes Problem.

Nach dem ersten Mal hochfahren, friert Mac OS plötzlich ein bzw. der Mac startet einfach neu immer wieder neu.
Ich muss danach mittels ein Ein/Aus Schalter den Mac abschalten und neu starten, d.h. nach den 2ten Start des Mac Pro funktioniert alles tadellos.

Hier mal der Bericht vom letzten Absturz:
Anonymous UUID: 1056F173-3537-D6C9-0BF8-43193AB728E1

Sun Aug 20 13:49:56 2017

*** Panic Report ***
Machine-check capabilities: 0x0000000000000806
family: 6 model: 23 stepping: 6 microcode: 1551
signature: 0x10676
Intel(R) Xeon(R) CPU X5472 @ 3.00GHz
6 error-reporting banks
Processor 0: IA32_MCG_STATUS: 0x0000000000000005
IA32_MC5_STATUS(0x415): 0xb200001084200e0f
Processor 1: IA32_MCG_STATUS: 0x0000000000000005
IA32_MC5_STATUS(0x415): 0xb200001080200e0f
Processor 2: IA32_MCG_STATUS: 0x0000000000000005
IA32_MC5_STATUS(0x415): 0xb200000084200e0f
Processor 3: IA32_MCG_STATUS: 0x0000000000000005
IA32_MC5_STATUS(0x415): 0xb200000080200e0f
Processor 4: IA32_MCG_STATUS: 0x0000000000000005
IA32_MC5_STATUS(0x415): 0xb200001084200e0f
Processor 5: IA32_MCG_STATUS: 0x0000000000000005
IA32_MC5_STATUS(0x415): 0xb200001080200e0f
Processor 6: IA32_MCG_STATUS: 0x0000000000000005
IA32_MC5_STATUS(0x415): 0xb200000084200e0f
Processor 7: IA32_MCG_STATUS: 0x0000000000000005
IA32_MC5_STATUS(0x415): 0xb200000080200e0f
panic(cpu 1 caller 0xffffff801981796a): "Machine Check at 0xffffff801980a92a, registers:\n" "CR0: 0x000000008001003b, CR2: 0xffffff80fb20e000, CR3: 0x000000001c3c9000, CR4: 0x0000000000002660\n" "RAX: 0x0000000000000001, RBX: 0xffffff802a8b0df8, RCX: 0x0000000009000000, RDX: 0xffffff802a8b0df8\n" "RSP: 0xffffff8124a6bda0, RBP: 0xffffff8124a6bda0, RSI: 0x0000000000000018, RDI: 0xffffff802a8b0df8\n" "R8: 0x000000000000000a, R9: 0xffffff802b054940, R10: 0xffffff802bb2edc0, R11: 0x0000000000000005\n" "R12: 0x0000000000000000, R13: 0xffffff802a8b0da0, R14: 0x0000000000000100, R15: 0xffffff802ce6f100\n" "RFL: 0x0000000000000206, RIP: 0xffffff801980a92a, CS: 0x0000000000000008, SS: 0x0000000000000010\n" "Error code: 0x0000000000000000\n"@/SourceCache/xnu/xnu-2782.70.3/osfmk/i386/trap_native.c:168
Backtrace (CPU 1), Frame : Return Address
0xffffff811b284e90 : 0xffffff801972ae01
0xffffff811b284f10 : 0xffffff801981796a
0xffffff811b285070 : 0xffffff80198346df
0xffffff8124a6bda0 : 0xffffff80197677e1
0xffffff8124a6be90 : 0xffffff8019c60ddb
0xffffff8124a6beb0 : 0xffffff8019cb3225
0xffffff8124a6bf30 : 0xffffff8019cae583
0xffffff8124a6bf70 : 0xffffff8019cb4493
0xffffff8124a6bfb0 : 0xffffff8019811867

BSD process name corresponding to current thread: kernel_task

Mac OS version:
14F2511

Kernel version:
Darwin Kernel Version 14.5.0: Sun Jun 4 21:40:08 PDT 2017; root:xnu-2782.70.3~1/RELEASE_X86_64
Kernel UUID: 9CB959EF-B0D4-3046-98E1-53536EA95A4F
Kernel slide: 0x0000000019400000
Kernel text base: 0xffffff8019600000
__HIB text base: 0xffffff8019500000
System model name: MacPro3,1 (Mac-F42C88C8)

System uptime in nanoseconds: 25086760772
last loaded kext at 24814141622: com.apple.driver.AppleMCEDriver 1.1.9 (addr 0xffffff7f9b790000, size 28672)
loaded kexts:
com.apple.driver.AppleFIVRDriver 4.1.0
com.apple.driver.AppleMCEDriver 1.1.9
com.apple.nvidia.NVDAStartup 10.0.4
com.apple.driver.AudioAUUC 1.70
com.apple.driver.AppleIntelSlowAdaptiveClocking 4.0.0
com.apple.driver.ACPI_SMC_PlatformPlugin 1.0.0
com.apple.driver.CSRHIDTransitionDriver 4.3.6f4
com.apple.driver.CoreStorageFsck 471.30.1
com.apple.iokit.SCSITaskUserClient 3.7.5
com.apple.driver.XsanFilter 404
com.apple.driver.AppleFileSystemDriver 3.0.1
com.apple.AppleFSCompression.AppleFSCompressionTypeDataless 1.0.0d1
com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0
com.apple.BootCache 36
com.apple.iokit.IOAHCIBlockStorage 2.7.1
com.apple.iokit.IOAHCIPassThrough 1.0.3
com.apple.driver.AppleIntel8254XEthernet 3.1.4b1
com.apple.driver.AppleUSBHub 705.4.2
com.apple.driver.AppleFWOHCI 5.5.2
com.apple.driver.AppleAHCIPort 3.1.2
com.apple.driver.AirPortBrcm43224 700.36.24
com.apple.driver.AppleIntelPIIXATA 2.5.1
com.apple.driver.AppleUSBEHCI 705.4.14
com.apple.driver.AppleUSBUHCI 656.4.1
com.apple.driver.AppleACPIButtons 3.1
com.apple.driver.AppleRTC 2.0
com.apple.driver.AppleHPET 1.8
com.apple.driver.AppleSMBIOS 2.1
com.apple.driver.AppleACPIEC 3.1
com.apple.driver.AppleAPIC 1.7
com.apple.driver.AppleIntelCPUPowerManagementClient 218.0.0
com.apple.nke.applicationfirewall 161
com.apple.security.quarantine 3
com.apple.security.TMSafetyNet 8
com.apple.driver.AppleIntelCPUPowerManagement 218.0.0
com.apple.iokit.IOUSBUserClient 705.4.0
com.apple.iokit.IOGraphicsFamily 2.4.1
com.apple.iokit.IOSlowAdaptiveClockingFamily 1.0.0
com.apple.driver.AppleSMC 3.1.9
com.apple.driver.IOPlatformPluginLegacy 1.0.0
com.apple.driver.IOPlatformPluginFamily 5.9.1d7
com.apple.driver.AppleUSBHIDKeyboard 176.2
com.apple.driver.AppleHIDKeyboard 176.2
com.apple.iokit.IOUSBHIDDriver 705.4.0
com.apple.driver.AppleUSBAudio 295.23
com.apple.iokit.IOAudioFamily 203.3
com.apple.vecLib.kext 1.2.0
com.apple.driver.AppleUSBMergeNub 705.4.0
com.apple.iokit.IOSCSIBlockCommandsDevice 3.7.5
com.apple.iokit.IOUSBMassStorageClass 3.7.2
com.apple.driver.AppleUSBComposite 705.4.9
com.apple.driver.CoreStorage 471.30.1
com.apple.iokit.IOSCSIMultimediaCommandsDevice 3.7.5
com.apple.iokit.IOBDStorageFamily 1.7
com.apple.iokit.IODVDStorageFamily 1.7.1
com.apple.iokit.IOCDStorageFamily 1.7.1
com.apple.iokit.IOATAPIProtocolTransport 3.5.0
com.apple.iokit.IOSCSIArchitectureModelFamily 3.7.5
com.apple.iokit.IOFireWireFamily 4.5.8
com.apple.iokit.IOAHCIFamily 2.7.5
com.apple.iokit.IO80211Family 730.60
com.apple.iokit.IONetworkingFamily 3.2
com.apple.iokit.IOATAFamily 2.5.3
com.apple.iokit.IOUSBFamily 720.4.4
com.apple.driver.AppleEFINVRAM 2.0
com.apple.driver.AppleEFIRuntime 2.0
com.apple.iokit.IOHIDFamily 2.0.0
com.apple.iokit.IOSMBusFamily 1.1
com.apple.security.sandbox 300.0
com.apple.kext.AppleMatch 1.0.0d1
com.apple.driver.AppleKeyStore 2
com.apple.driver.AppleMobileFileIntegrity 1.0.5
com.apple.driver.AppleCredentialManager 1.0
com.apple.driver.DiskImages 398
com.apple.iokit.IOStorageFamily 2.0
com.apple.iokit.IOReportFamily 31
com.apple.driver.AppleFDEKeyStore 28.30
com.apple.driver.AppleACPIPlatform 3.1
com.apple.iokit.IOPCIFamily 2.9
com.apple.iokit.IOACPIFamily 1.4
com.apple.kec.corecrypto 1.0
com.apple.kec.Libm 1
com.apple.kec.pthread 1
Model: MacPro3,1, BootROM MP31.006C.B05, 8 processors, Quad-Core Intel Xeon, 3 GHz, 8 GB, SMC 1.25f4
Graphics: NVIDIA Quadro FX 5600, NVIDIA Quadro FX 5600, PCIe, 1536 MB
Memory Module: DIMM Riser B/DIMM 1, 1 GB, DDR2 FB-DIMM, 800 MHz, 0x80AD, 0x48594D5035313241373243503844332D5335
Memory Module: DIMM Riser B/DIMM 2, 1 GB, DDR2 FB-DIMM, 800 MHz, 0x0198, -
Memory Module: DIMM Riser A/DIMM 1, 1 GB, DDR2 FB-DIMM, 800 MHz, 0x80AD, 0x48594D5035313241373243503844332D5335
Memory Module: DIMM Riser A/DIMM 2, 1 GB, DDR2 FB-DIMM, 800 MHz, 0x0198, -
Memory Module: DIMM Riser B/DIMM 3, 1 GB, DDR2 FB-DIMM, 800 MHz, 0x0198, 0x4B494E4753544F4E20202020202020202020
Memory Module: DIMM Riser B/DIMM 4, 1 GB, DDR2 FB-DIMM, 800 MHz, 0x0198, 0x4B494E4753544F4E20202020202020202020
Memory Module: DIMM Riser A/DIMM 3, 1 GB, DDR2 FB-DIMM, 800 MHz, 0x0198, 0x4B494E4753544F4E20202020202020202020
Memory Module: DIMM Riser A/DIMM 4, 1 GB, DDR2 FB-DIMM, 800 MHz, 0x0198, 0x4B494E4753544F4E20202020202020202020
AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0x88), Broadcom BCM43xx 1.0 (5.10.131.36.16)
Bluetooth: Version 4.3.6f4 17916, 3 services, 18 devices, 1 incoming serial ports
Network Service: Wi-Fi, AirPort, en2
PCI Card: NVIDIA Quadro FX 5600, Display Controller, Slot-1
Serial ATA Device: WDC WD5000AZRX-00A8LB0, 500,11 GB
Serial ATA Device: ST3160023AS, 160,04 GB
Serial ATA Device: WDC WD5000AVDS-63U7B1, 500,11 GB
Serial ATA Device: WDC WD3200AAKX-001CA0, 320,07 GB
Parallel ATA Device: HL-DT-STDVD-RAM GH22NP20
USB Device: USB2.0 Hub
USB Device: Microsoft® LifeCam HD-3000
USB Device: Keyboard Hub
USB Device: USB-PS/2 Optical Mouse
USB Device: Apple Keyboard
USB Device: MG7100 series
USB Device: Bluetooth USB Host Controller
FireWire Device: built-in_hub, Up to 800 Mb/sec
Thunderbolt Bus:

Woran könnte das Problem liegen?

Vielen Dank vorab

lg
Daniel