Hello, with which cable is your screen connected? DVI or Display port? I had several worries with cables Display port in standby outputs (MacPro with Nvidia and sierra) and I almost failed to be able to restart the Mac. I ended up abandoning the Display port cables for a DVI which is no longer a problem.
I have both DVI and Displayport, neither worked.
UPDATE:
tried it this morning and it booted up and the screen came on, I copied the crash report error here:
Anonymous UUID: 92A6A830-A82B-8C28-4AC5-9F58BE0F7B01
Wed Oct 4 09:43:19 2017
*** Panic Report ***
panic(cpu 8 caller 0xffffff8015abadfd): "a freed zone element has been modified in zone kalloc.16: expected 0xe4988e0afe0854d4 but found 0xdeadbeef00000001, bits changed 0x3a3530e5fe0854d5, at offset 0 of 16 in element 0xffffff8042d90440, cookies 0x3f00118bd08232d6 0x535216ef027d8ed"@/BuildRoot/Library/Caches/com.apple.xbs/Sources/xnu/xnu-4570.1.46/osfmk/kern/zalloc.c:1120
Backtrace (CPU 8), Frame : Return Address
0xffffff82dc9c3780 : 0xffffff8015a6d366
0xffffff82dc9c37c0 : 0xffffff8015b98494
0xffffff82dc9c3800 : 0xffffff8015b8a429
0xffffff82dc9c3880 : 0xffffff8015a1f190
0xffffff82dc9c38a0 : 0xffffff8015a6cd8c
0xffffff82dc9c39d0 : 0xffffff8015a6cafc
0xffffff82dc9c3a30 : 0xffffff8015abadfd
0xffffff82dc9c3a90 : 0xffffff8015aba6d0
0xffffff82dc9c3ae0 : 0xffffff8015ab9113
0xffffff82dc9c3c10 : 0xffffff8015a789f4
0xffffff82dc9c3c50 : 0xffffff801603f98b
0xffffff82dc9c3c90 : 0xffffff8016041f37
0xffffff82dc9c3cc0 : 0xffffff80160701c2
0xffffff82dc9c3ce0 : 0xffffff80160703a0
0xffffff82dc9c3d20 : 0xffffff7f96995c0f
0xffffff82dc9c3dc0 : 0xffffff7f96995576
0xffffff82dc9c3e20 : 0xffffff7f96994fd7
0xffffff82dc9c3e40 : 0xffffff801607e18d
0xffffff82dc9c3e80 : 0xffffff801607ded1
0xffffff82dc9c3f00 : 0xffffff801607d3f7
0xffffff82dc9c3f50 : 0xffffff801607f006
0xffffff82dc9c3fa0 : 0xffffff8015a1c4f7
Kernel Extensions in backtrace:
com.apple.iokit.IOStorageFamily(2.1)[0E8BC828-5A1E-3308-ADAB-1F4373F9402F]@0xffffff7f9698a000->0xffffff7f969b0fff
BSD process name corresponding to current thread: kernel_task
Boot args: rp=file:///Backups.backupdb/.RecoverySets/1/com.apple.recovery.boot/BaseSystem.dmg
Mac OS version:
Not yet set
Kernel version:
Darwin Kernel Version 17.0.0: Thu Aug 24 21:48:19 PDT 2017; root:xnu-4570.1.46~2/RELEASE_X86_64
Kernel UUID: B84FDEFC-9081-35CE-8C51-25A9583AACDE
Kernel slide: 0x0000000015800000
Kernel text base: 0xffffff8015a00000
__HIB text base: 0xffffff8015900000
System model name: MacPro5,1 (Mac-F221BEC8)
System uptime in nanoseconds: 2195016653
last loaded kext at 2187701326: com.apple.driver.AppleXsanScheme 3 (addr 0xffffff7f98cdf000, size 40960)
loaded kexts:
com.apple.driver.AppleFileSystemDriver 3.0.1
com.apple.driver.AppleFWOHCI 5.5.8
com.apple.filesystems.hfs.kext 407.1.3
com.apple.driver.Intel82574LEthernet 2.7.2
com.apple.BootCache 40
com.apple.driver.AirPort.Brcm4331 800.20.26
com.apple.AppleFSCompression.AppleFSCompressionTypeDataless 1.0.0d1
com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0
com.apple.driver.AppleAHCIPort 329
com.apple.driver.AppleRTC 2.0
com.apple.driver.AppleHPET 1.8
com.apple.driver.AppleACPIButtons 6.1
com.apple.driver.AppleSMBIOS 2.1
com.apple.driver.AppleACPIEC 6.1
com.apple.driver.AppleAPIC 1.7
com.apple.driver.AppleIntelCPUPowerManagementClient 220.0.0
com.apple.nke.applicationfirewall 183
com.apple.security.TMSafetyNet 8
com.apple.security.quarantine 3
com.apple.driver.AppleIntelCPUPowerManagement 220.0.0
com.apple.IOBufferCopyEngineTest 1
com.apple.driver.AppleXsanScheme 3
com.apple.iokit.IOAHCIBlockStorage 301.1.2
com.apple.iokit.IOAHCISerialATAPI 267
com.apple.iokit.BroadcomBluetoothHostControllerUSBTransport 6.0.0f7
com.apple.iokit.IOBluetoothHostControllerUSBTransport 6.0.0f7
com.apple.iokit.IOBluetoothHostControllerTransport 6.0.0f7
com.apple.driver.usb.AppleUSBHub 1.2
com.apple.iokit.IOFireWireFamily 4.6.8
com.apple.iokit.IO80211Family 1200.12.2
com.apple.driver.corecapture 1.0.4
com.apple.driver.AppleUSBMergeNub 900.4.1
com.apple.filesystems.hfs.encodings.kext 1
com.apple.iokit.IOAHCIFamily 288
com.apple.driver.usb.AppleUSBEHCIPCI 1.2
com.apple.driver.usb.AppleUSBUHCIPCI 1.2
com.apple.driver.usb.AppleUSBUHCI 1.2
com.apple.driver.usb.AppleUSBEHCI 1.2
com.apple.driver.usb.AppleUSBHostPacketFilter 1.0
com.apple.iokit.IOUSBFamily 900.4.1
com.apple.driver.AppleUSBHostMergeProperties 1.2
com.apple.driver.AppleEFINVRAM 2.1
com.apple.driver.AppleEFIRuntime 2.1
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.iokit.IOBufferCopyEngineFamily 1
com.apple.driver.AppleKeyStore 2
com.apple.driver.AppleUSBTDM 439
com.apple.driver.AppleMobileFileIntegrity 1.0.5
com.apple.iokit.IOUSBMassStorageDriver 140
com.apple.iokit.IOSCSIBlockCommandsDevice 404
com.apple.iokit.IOSCSIArchitectureModelFamily 404
com.apple.driver.AppleCredentialManager 1.0
com.apple.driver.KernelRelayHost 1
com.apple.driver.AppleSEPManager 1.0.1
com.apple.driver.IOSlaveProcessor 1
com.apple.iokit.IOTimeSyncFamily 600.15
com.apple.iokit.IONetworkingFamily 3.3
com.apple.driver.DiskImages 480.1.2
com.apple.iokit.IOStorageFamily 2.1
com.apple.iokit.IOBluetoothFamily 6.0.0f7
com.apple.iokit.IOUSBHostFamily 1.2
com.apple.driver.usb.AppleUSBCommon 1.0
com.apple.driver.AppleBusPowerController 1.0
com.apple.iokit.IOReportFamily 31
com.apple.driver.AppleFDEKeyStore 28.30
com.apple.driver.AppleACPIPlatform 6.1
com.apple.driver.AppleSMCRTC 1.0
com.apple.driver.AppleSMC 3.1.9
com.apple.iokit.IOPCIFamily 2.9
com.apple.iokit.IOACPIFamily 1.4
com.apple.kec.Libm 1
com.apple.kec.pthread 1
com.apple.kec.corecrypto 1.0
EOF
Model: MacPro5,1, BootROM MP51.0084.B00, 6 processors, 6-Core Intel Xeon, 3.46 GHz, 24 GB, SMC 1.39f11
Graphics: NVIDIA GeForce GTX 680, NVIDIA GeForce GTX 680, PCIe, 2 GB
Memory Module: DIMM 1, 8 GB, DDR3 ECC, 1333 MHz, 0x0198, 0x393936353531362D3030312E4230304C4620
Memory Module: DIMM 2, 8 GB, DDR3 ECC, 1333 MHz, 0x0198, 0x393936353434372D3036332E4130304C4620
Memory Module: DIMM 3, 8 GB, DDR3 ECC, 1333 MHz, 0x0198, 0x393936353531362D3033362E4130304C4620
AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0x8E), Broadcom BCM43xx 1.0 (5.106.98.100.26)
Bluetooth: Version 6.0.0f7, 3 services, 27 devices, 1 incoming serial ports
Network Service: Ethernet 1, Ethernet, en0
Network Service: Wi-Fi, AirPort, en2
PCI Card: NVIDIA GeForce GTX 680, Display Controller, Slot-1
PCI Card: NVIDIA GeForce GTX 680, NVDA,Parent, Slot-1
PCI Card: pci144d,a801, AHCI Controller, Slot-4
Serial ATA Device: SAMSUNG MZHPV256HDGL-00000, 256.06 GB
Serial ATA Device: HL-DT-ST DVD-RW GH61N
Serial ATA Device: WDC WD40EFRX-68N32N0, 4 TB
Serial ATA Device: Hitachi HDS5C4040ALE630, 4 TB
Serial ATA Device: WDC WD40EFRX-68WT0N0, 4 TB
Serial ATA Device: WDC WD40EFRX-68WT0N0, 4 TB
USB Device: USB Bus
USB Device: USB Bus
USB Device: BRCM2046 Hub
USB Device: Bluetooth USB Host Controller
USB Device: USB Bus
USB Device: USB Bus
USB Device: USB Bus
USB Device: USB Bus
USB Device: USB 2.0 Bus
USB Device: USB 2.0 Bus
FireWire Device: built-in_hub, Up to 800 Mb/sec
Thunderbolt Bus: