How does Windows utilize Hyperthreaded cores? - The Workshop

Hyperthreading is a long standing feature on high end Intel CPUs, but the Workshop episode sets out to demystify what actually happens inside Windows when you run multi threading on a hyperthreaded quad core. The presenter begins by clarifying the difference between physical cores and logical cores, explaining that four physical cores can present eight logical cores due to hyperthreading, and that these eight logical units are not equal to eight real cores. He demonstrates how Windows Task Manager shows eight CPUs on a system with a hyperthreaded CPU and emphasizes that the eight logical cores do not translate to eight physical cores. By setting up two Windows virtual machines with four logical cores each and running benchmarks, he tests whether Windows cares which logical core is allocated to a VM and whether there is any performance advantage to using one logical thread over another. The results show minimal differences between individual logical cores when benchmarked separately, but a small performance dip when both VMs run simultaneously, illustrating that hyperthreading can improve utilization of a physical core but does not create a clean one-to-one improvement in performance. The discussion then turns to practical implications, noting that hyperthreading enables better utilization of CPU cycles by allowing two threads to share a single physical core when resources permit, rather than doubling performance. The takeaway is clear: you do not have eight physical cores, but you can leverage four physical cores more effectively through hyperthreading, while recognizing that the logical cores are equivalent in Windows’ scheduling context. The episode ends with a quick reminder that this is a tuning and understanding exercise, not a wholesale replacement of physical cores, followed by sponsorship plugs and a promo for Massdrop products.

Topics · technology · computer-hardware · operating-systems · performance-benchmarks