I added a rtl8139c netcard to the VM and connected through it by RDP - no more freezes.
It looks like kvm does not play well with virtio network cards and RDP.
Red Hat virtio net windows driver version: 62.65.104.6500, 6/19/2013
I left the RH adapter on the VM, I just connect via RDP through the rtl8139c network card.
I added a rtl8139c netcard to the VM and connected through it by RDP - no more freezes.
It looks like kvm does not play well with virtio network cards and RDP.
Red Hat virtio net windows driver version: 62.65.104.6500, 6/19/2013
I left the RH adapter on the VM, I just connect via RDP through the rtl8139c network card.