The "CPU mutex" is just the cache coherency mechanism. If you shard your data to avoid triggering it as suggested, then yes, it's much faster.
EDIT: or maybe you're asking if introducing an explicit userspace mutex is better than a lockless algorithm with false sharing issues. The answer is that it's workload dependent but it definitely can be.
EDIT: or maybe you're asking if introducing an explicit userspace mutex is better than a lockless algorithm with false sharing issues. The answer is that it's workload dependent but it definitely can be.