Mac Tower 4.1 Freezing once a day

Hello, Every day when I boot my machine at some point it will freeze. I can restart and it will not freeze again. When I shut down for the night and start up the next day the same problem persists. I just changed out all the RAM and that did not solve the problem. Prior to that I zapped the PRAM, changed the internal battery. I ran tests on the internal hard drives and all report back OK. I have attached the crash log. Any help would be great. Thanks

Interval Since Last Panic Report: 21722 sec

Panics Since Last Report: 1

Anonymous UUID: EFDCCFF2-E0D5-A588-7FF7-88BA91BEAC4D

Thu Oct 29 09:28:40 2015

Machine-check capabilities 0x0000000000001c09:

family: 6 model: 26 stepping: 5 microcode: 17

Intel(R) Xeon(R) CPU X5550 @ 2.67GHz

9 error-reporting banks

threshold-based error status present

extended corrected memory error handling present

Processor 0: no valid machine-check state

Processor 1: no valid machine-check state

Processor 2: no valid machine-check state

Processor 3: no valid machine-check state

Processor 4: no valid machine-check state

Processor 5: no valid machine-check state

Processor 6: no valid machine-check state

Processor 7: no valid machine-check state

Processor 8: machine-check status 0x0000000000000004:

machine-check in progress

MCA error-reporting registers:

IA32_MC0_STATUS(0x401): 0x0000000000000800 invalid

IA32_MC1_STATUS(0x405): 0xbe00000000400e0f valid

MCA error code: 0x0e0f

Model specific error code: 0x0040

Model: MacPro4,1, BootROM MP41.0081.B07, 8 processors, Quad-Core Intel Xeon, 2.66 GHz, 32 GB, SMC 1.39f5

Graphics: ATI Radeon HD 4870, ATI Radeon HD 4870, PCIe, 512 MB

Memory Module: DIMM 1, 4 GB, DDR3 ECC, 1066 MHz, 0x85F7, 0x463732353155363246393333334700520000

Memory Module: DIMM 2, 4 GB, DDR3 ECC, 1066 MHz, 0x85F7, 0x463732353155363246393333334700520000

Memory Module: DIMM 3, 4 GB, DDR3 ECC, 1066 MHz, 0x85F7, 0x463732353155363246393333334700520000

Memory Module: DIMM 4, 4 GB, DDR3 ECC, 1066 MHz, 0x85F7, 0x463732353155363246393333334700520000

Memory Module: DIMM 5, 4 GB, DDR3 ECC, 1066 MHz, 0x85F7, 0x463732353155363246393333334700520000

Memory Module: DIMM 6, 4 GB, DDR3 ECC, 1066 MHz, 0x85F7, 0x463732353155363246393333334700520000

Memory Module: DIMM 7, 4 GB, DDR3 ECC, 1066 MHz, 0x85F7, 0x463732353155363246393333334700520000

Memory Module: DIMM 8, 4 GB, DDR3 ECC, 1066 MHz, 0x85F7, 0x463732353155363246393333334700520000

AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0x8E), Broadcom BCM43xx 1.0 (5.106.98.100.17)

Bluetooth: Version 4.1.7f5 15113, 3 service, 13 devices, 3 incoming serial ports

Network Service: AirPort, AirPort, en2

PCI Card: ATI Radeon HD 4870, sppci_displaycontroller, Slot-1

PCI Card: pci1b4b,9123, sppci_ahci, Slot-3

PCI Card: pci1b4b,91a4, sppci_ide, Slot-3

PCI Card: pcibdbd,a117, sppci_video, Slot-4

Serial ATA Device: HL-DT-ST DVDRAM GH24NS95

Serial ATA Device: HL-DT-ST DVD-RW GH41N

Serial ATA Device: ST31500341AS, 1.5 TB

Serial ATA Device: ST2000DM001-1CH164, 2 TB

Serial ATA Device: ST2000DM001-9YN164, 2 TB

Serial ATA Device: WDC WD15EADS-00P8B0, 1.5 TB

USB Device: hub_device, apple_vendor_id, 0x9136, 0xfa200000 / 2

USB Device: hub_device, apple_vendor_id, 0x9137, 0xfa240000 / 3

USB Device: Display iSight, apple_vendor_id, 0x8508, 0xfa242000 / 6

USB Device: Display Audio, apple_vendor_id, 0x2912, 0xfa241000 / 5

USB Device: Apple LED Cinema Display, apple_vendor_id, 0x9236, 0xfa243000 / 4

USB Device: Keyboard Hub, apple_vendor_id, 0x1006, 0xfd300000 / 2

USB Device: Apple Optical USB Mouse, apple_vendor_id, 0x0304, 0xfd330000 / 4

USB Device: Apple Keyboard, apple_vendor_id, 0x0220, 0xfd320000 / 3

USB Device: BRCM2046 Hub, 0x0a5c (Broadcom Corp.), 0x4500, 0x5a100000 / 2

USB Device: Bluetooth USB Host Controller, apple_vendor_id, 0x8215, 0x5a110000 / 5

FireWire Device: built-in_hub, 800mbit_speed