[libvirt-users] Guest's CPU frequency cannot be similar to host system

My resource: kernel: 4.16.8 host system: Ubuntu 16.04 Llbvirt : 4.2 Qemu : 2.12 Cpu : intel@core i7 6700 guest system: windows7 professional My problem: In my host, Cpu frequency is 3800~3900 MHz(4 socket and 2 thread) because i turn on “Intel Turbo Boost”. And silent frequency is 3.40 GHz. Then i boot my guest, But in Guest my cpu frequency is 3408 MHz. why it's not 3800 MHz? And here is my guest xml: <cpu mode='host-passthrough' check='none'> <topology sockets='1' cores='8' threads='1'/> </cpu>