Are you sure, should not be '-smp
4,sockets=1,cores=2,threads=4' for
dual core / quad thread CPU?
sockets=1,cores=2,threads=4 will emulate a non existing (in the x86
world) dual core / 8 threads CPU.
If you want to emulate a 6 core Xeon CPU, you'll need
sockets=1,cores=6,threads=2.
- Gilboa