I have tried the following cards...

GT 640 2GB

Nvidia Quatro 2000

Nvidia Quadro NVR 295

8400GS Gen2 (very old card.)

 

I can get ubuntu to output and complain about low graphics screen. but I can not get windows to do anything on the screen.

 

Computer Specs:

• HP Z620 Workstation
• Dual 6 core Intel® Xeon® CPU E5-2640 @ 2.50GHz
• 12GB RAM (will be upgrading soon)
• 3 1TB (1 parity)
• 256GB SSD cache

 

 

the computer can support dual GPU's I have verified that all the tested GPU's work before I put them into passthrough.

 

I have tried to do the whole 

<rom file='/mnt/user//vbios/gt640.dump'/>

but nothing has let me output windows on a dedicated monitor.

 

I have tried windows 8.1 and windows server 2012 R2

 

my only goal here.

have ubuntu and windows running at the same time with 2 different Graphics Cards so I can multi task with 2 different OS's at the same time..

 

 

Windows Log File:
 

2017-08-21 15:49:30.088+0000: starting up libvirt version: 2.4.0, qemu version: 2.7.1, hostname: tower
LC_ALL=C PATH=/bin:/sbin:/usr/bin:/usr/sbin HOME=/ QEMU_AUDIO_DRV=none /usr/local/sbin/qemu -name 'guest=Windows 8.1,debug-threads=on' -S -object 'secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-5-Windows 8.1/master-key.aes' -machine pc-i440fx-2.7,accel=kvm,usb=off,dump-guest-core=off,mem-merge=off -cpu host -drive file=/usr/share/qemu/ovmf-x64/OVMF_CODE-pure-efi.fd,if=pflash,format=raw,unit=0,readonly=on -drive file=/etc/libvirt/qemu/nvram/f65492cd-aedc-feb8-74c3-a3dc6bb25f9a_VARS-pure-efi.fd,if=pflash,format=raw,unit=1 -m 2048 -realtime mlock=off -smp 1,sockets=1,cores=1,threads=1 -uuid f65492cd-aedc-feb8-74c3-a3dc6bb25f9a -display none -no-user-config -nodefaults -chardev 'socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-5-Windows 8.1/monitor.sock,server,nowait' -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime,driftfix=slew -global kvm-pit.lost_tick_policy=discard -no-hpet -no-shutdown -boot strict=on -device ich9-usb-ehcaddr=0x2 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev 'socket,id=charchannel0,path=/var/lib/libvirt/qemu/channel/target/domain-5-Windows 8.1/org.qemu.guest_agent.0,server,nowait' -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0 -device vfio-pci,host=04:00.0,id=hostdev0,bus=pci.0,addr=0x5,romfile=/mnt/user/isos/VBIOS/n2000.dump -device vfio-pci,host=04:00.1,id=hostdev1,bus=pci.0,addr=0x6 -device usb-host,hostbus=2,hostaddr=4,id=hostdev2,bus=usb.0,port=1 -device usb-host,hostbus=2,hostaddr=3,id=hostdev3,bus=usb.0,port=2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x8 -msg timestamp=on
Domain id=5 is tainted: high-privileges
Domain id=5 is tainted: host-cpu
char device redirected to /dev/pts/0 (label charserial0)

 

Edited August 21, 20178 yr by cheabred
more info

OK so for anyone else that has this issue. remake the VM and put the BIOS as SeaBIOS due to it defaulting to OVMF  literally worked the very first time.

I had no trouble creating a Windows10 VM with GPU passthrough with OVMF.  My understanding is that SeaBIOS is used when the boot disks is MBR (<2.2T), and OVMF is used when it is GPT (any size boot partition). Not sure there is tremendous advantage to either, but GPT seems to be the way of the future.