This is off-topic and trivial. Anyway, IMO speedhacks are features that can increase performance but aren't designed to work correctly in all cases. If it doesn't work in some cases, it's probably because it's a hack. You just disable it. On the other hand, core features are supposed to work correctly in all cases. If it doesn't work, it's a bug and the developers should fix it. Being default and recommended setting doesn't mean it's not a speedhack.
If you have used PCSX2, you will see many recommended speedhacks but dual-core isn't one of them. In PCSX2, dual-core is a core feature and it has MTVU (3 cores) as a recommended speedhack for 3+ cores.
If you have used PCSX2, you will see many recommended speedhacks but dual-core isn't one of them. In PCSX2, dual-core is a core feature and it has MTVU (3 cores) as a recommended speedhack for 3+ cores.