performance: 0.971
virtual: 0.968
graphic: 0.967
boot: 0.948
device: 0.935
peripherals: 0.772
ppc: 0.754
semantic: 0.685
PID: 0.639
socket: 0.573
vnc: 0.492
VMM: 0.483
permissions: 0.479
hypervisor: 0.452
arm: 0.449
mistranslation: 0.446
register: 0.425
architecture: 0.411
user-level: 0.389
risc-v: 0.338
debug: 0.325
TCG: 0.303
files: 0.245
assembly: 0.186
kernel: 0.114
i386: 0.086
x86: 0.084
network: 0.054
KVM: 0.017

i440fx ide cdrom pathological slow on early win10 install  screen
Description of problem:
if you choose i440fx virtual hardware (default in proxmox) for windows 10 instead of q35 , from power on to the windows boot logo is 10 times slower.  you need to wait more then 1m45s on my hardware until the blinking cursor in the upper left goes away and the blue windows bootlogo appears. that leads to false assumption, that your setup hangs. 

what's causing this slownewss?

is implementation really that bad?

i did compare read performance of ide, sata and scsi cdrom in linux vm and cannot observe such a big difference.

see
https://forum.proxmox.com/threads/win10-installation-pathological-slowness-with-i440fx-ide-cdrom.129351/