Intel to Resurrect Hyper-Threading in Symmetric Multi-Processing
Intel is to resurrect Hyper-Threading with its Nehalem microarchitecture and system architecture (latter half ‘08). It shall be called Symmetric Multi-Threading (SMT), however, not Hyper-Threading (HT).
The idea is simple. Take the individual cores of CPUs and have the OS and applications see each core as two cores instead of one. That way you can do twice as much work. Twice as much? Well, maybe not. But that way the processor can process two threads at a time, rather than just one.
In truth, running two threads inside a core using Hyper-Threading is not that big of a deal. Adding cores is a much bigger deal–provided the software can take advantage of the cores.
Look at the first incarnation of SMT, Hyper-Threading (HT), and how it fared against the Athlon X2, or even the Pentium D. None too great. It wasn’t that HT was bad. The technology was great. But HT didn’t pack the punch that a genuine two cores could. Typical computing scenario. Better performance, just not as good as someone else’s performance. Sound familiar?
Maybe it was the performance of Hyper-Threading when stacked up against genuine dual-cores that led to Intel scrapping projects that were on its published roadmap and accelerating its genuine dual- and multi-core programs instead.