[libvirt-users] win2k8 guest and (strange) number of cpus task manager sees

hi everybody a qemu-kvm guest gets 16 cpus and Windows in "Device Manager" sees all sixteeen but "Task Manager" shows only 4, the same "System" properties say "(4 processors)" I'd like to learn a bit about this - is it some sort of "resources management" on the libvirt/qemu causing this? And what does it do to a guest performance-wise side? it's on Scientific L 7, qemu-kvm-1.5.3-60.el7_0.7.x86_64 libvirt-1.1.1-29.el7_0.1.x86_64 regards P.