Hello, Thanks for your answer. My virsh capabilities is the following : <cpu> <arch>x86_64</arch> <model>pentium3</model> <vendor>Intel</vendor> <topology sockets='1' cores='4' threads='1'/> <feature name='lahf_lm'/> <feature name='lm'/> <feature name='syscall'/> <feature name='sse4.1'/> <feature name='dca'/> <feature name='xtpr'/> <feature name='cx16'/> <feature name='ssse3'/> <feature name='tm2'/> <feature name='est'/> <feature name='vmx'/> <feature name='ds_cpl'/> <feature name='monitor'/> <feature name='pni'/> <feature name='pbe'/> <feature name='tm'/> <feature name='ht'/> <feature name='ss'/> <feature name='sse2'/> <feature name='acpi'/> <feature name='ds'/> <feature name='clflush'/> <feature name='apic'/> </cpu> About what you say, I totally agree. It's just I am very surprised that an Intel Xeon E5430 is detected just as a pentium3