> I guess by queue he meant the processor internal work queue... Yes, I meant the internal one. Also, when you enable SMT, a small tag is added in front of eve

> I guess by queue he meant the processor internal work queue... Yes, I meant the internal one. Also, when you enable SMT, a small tag is added in front of every instruction, noting which logical core owns this instruction for a given physical core. So instead of tagging every instruction with a core-ID, you add a longer tag in the form of core-ID/logical_core-ID. This extra tagging also makes instructions bigger, so the queue can hold less instructions, adding fuel to already chaotic and choked FPU logistics. As a result, if you're saturating your FPU(s), SMT can't save you. In fact can make you slower.