Hyper-threading technology improves CPU efficiency by allowing the processor to execute two instruction streams concurrently. This feature, found on newer Intel Pentium 4 processors, can typically improve the performance of apps by 20 to 30 percent, boosting some apps by up to 40 percent. Unfortunately, other applications see no performance benefit, and a few can experience significant performance degradation (I've seen application degradation of as much as 20 percent), especially when violating recommended performance best practices such as the ones discussed in this article.
