We had a qlikview E2620 server (2.1Ghz , 8 cores, 126 GB RAM) virtualized on proxmox. We decided to change the processor to bring more power. We switched to an AMD EPYC 7302P (3Ghz, 16 cores, 256GB RAM).
We had during the transfer of the vm, quite a few problems with a windows process "system". It was consuming all the cpu resources at startup. It was doing a check on the ram, and all the processor was used. (99%).
My colleagues managed to solve this problem by dedicating 10% of the total ram to the hypervisor. Windows now starts normally.
I have some reloads that now take longer than before.
I would also suggest @David_Friend 's approach to compare where the extra time is spent. For example you could use Notepad++ and use the plugin named Compare and see where the extra time is used to narrow down the investigation. Plus, were you using the same QlikView version during such time and only the CPU was changed?
Please, remember to mark the thread as solved once getting the correct answer