no the problem is that the new qemu-kvm reorders the virtual pci cards...for me i had to fix the fixeds ips manually. and it it just a windows problem..my linux vms did not change
my last 2019 rdp server is really fast...change to q35 and do not use host cpu but a version before e.g. skylake-server-no-irbs...always use virtio drivers and my vm has 32gb of ram and turn off ballooning...but 8gb ram for a host is way too less.
That is simple. Change /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_idle.max_cstate=1 processor.max_cstate=1 audit=0"
after that run update-grub and reboot.
Also ich kann das nicht nachvollziehen. Wir haben nur Samba 4.12.3 Server im Einsatz (LXC auf ZFS) mit Multichannel und SMB3 bin ich schon auf 10Gbit intern gekommen und das von Windows 10 aus.