In libvirt/virt-manager, Win7 was successful because I can directly assign PCI-E device to boot device.
I finally know it's unable in Proxmox because I can't assign GPU to boot.
Windows 8.1, as I said above, it seems work normally but it doesn't show 3D part of screen.
(as I know till now)
Thank you for enduring my bad English, first. ^ _^ ;
I used KVM with libvirt (virt-manager) and 'migrated' to Proxmox recently.
I had succeeded GPU passthrough in libvirt with win7 win8.1 win10 but now I just do it with win10 with Proxmox.
(win 10 seems very easy as it requires 'almost' only...
Could I set Proxmox boot sequence as PCI device?
I installed windows 7 UEFI and I doesn't boot naturally but I choose PCI device manually
it boots normally.
Is there any way to set boot to PCI device as default?
(I found the setting is changed whenever my vm conf changes)
I found solution.