If you are running "top" (the Linux command) on your host server while this VM boots, you will notice the PFE image consumes the most CPU cycles during initialization as it initializes the virtual ASIC simulation.
The (Virtual QFX) is Juniper Networks’ virtualized version of their popular QFX Series switches, typically used as spine and leaf nodes in IP Clos / EVPN-VXLAN data center fabrics.