Ok, so x86_64_BUG_CPU_INSECURE will be optional in kernel config. As I read Meltdown is primary a security risk on server farms where multiple customers use same CPU. If I have my own private server on own hardware, and thereby have full control over software in use, then I might get a performance boost by not using x86_64_BUG_CPU_INSECURE and thereby use full standard speculative execution. Brgds Torben