Intel is wise to keep Hyper-Threading an integral part of its high-end processors. Our analysis shows that many applications can benefit significantly from the extra logical cores. The feature is naturally most effective in threaded apps. Software developers know where parallelism stands to benefit the performance of their titles most profoundly, and over the years, a majority have optimized their products to utilize the almost-ubiquitous ecosystem of dual-, triple-, and quad-core CPUs. Fritz, 3ds Max, Cinebench, MainConcept, and 7-Zip are but a few of the apps able to capitalize on the feature and demonstrate improved performance. Even clock speed increases can't yield these performance boosts, unless you really crank up the overclocking. In this regard, Hyper-Threading does a great job by further improving performance via augmented utilization in the workloads that need it most.
Unfortunately, these types of applications aren't necessarily universal on mainstream desktop PCs, and therein lies the rub. Many of the titles used in this article can't take advantage of additional parallelism. Gulftown’s six cores already provide plenty of performance, and whether Hyper-Threading is switched on or off doesn't make a ton of difference (until you start looking at power consumption, that is). Enabling Hyper-Threading clearly increases peak power. Conversely, disabling the feature helps to lower peak power.
In the end, efficiency increases with Hyper-Threading on Intel’s quad-core Core i7-975 Extreme Edition because many applications scale well at up to eight cores (or threads). The new Core i7-980X shows little benefit from Hyper-Threading, though, and even takes a slight efficiency hit. The conclusions we drew in our initial review hold up here. This isn't a gaming processor, and it's not particularly well-suited to the desktop at all. Rather, it's a workstation processor best suited to content creation, rendering, and other parallelized workloads. If you're not doing that sort of heavy lifting, a quad-core CPU like the Core i5-750/Phenom II X4 965 or even a Hyper-Threading-enabled quad-core chip like the Core i7-930 makes for a smarter buy.