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Experiment: Does Intel’s Turbo Boost Trump Overclocking?


At the end of the day, our explorations into the benefits of Turbo Boost, Hyper-Threading, and good old fashioned overclocking reveal some great bits of information.

First off, we know that Turbo Boost is most effective at improving the performance of poorly-threaded applications. While these are fewer and further between nowadays, we did have a couple of examples of apps that’d see a significant speed-up with Turbo turned on. We also noted a consistent performance increase with Turbo Boost turned on—even in threaded apps—thanks to a single bin of acceleration with four cores utilized. Briefly, intelligence built into these Nehalem-based CPUs gives Intel a competitive advantage over AMD and its older Core 2-based chips in titles like iTunes, WinZip, and Lame. Turbo Boost is less of a factor in MainConcept, HandBrake, WinRAR, and 7zip—effectively-coded apps that push quad-core CPUs harder through parallelism.

Hyper-Threading was helpful less often, but again there were a couple of situations where it made a palpable difference in real-world benchmarks. The video transcoding apps, for example, know how to take advantage of Hyper-Threading and shave seconds off of those workloads. With that said, there’s a good reason we’ve been so bullish on the Core i5-750. Priced almost $100 less than the Core i7-860, it serves up almost all of the same performance with only minimal sacrifices in properly-optimized programs. This continues to be today’s version of the famed Celeron 300A, which reliably scaled to 450 MHz.

The big winner continues to be manual overclocking. While we appreciate value-adds like Turbo Boost in the Core i5 and Core i7 chips, it’s important to note that the technology’s benefit is most apparent in single-threaded workloads (becoming less prevalent as developers take advantage of today’s multi-core architectures). It all but disappears when you apply a more demanding metric. Meanwhile, the gains associated with overclocking are accessible all of the time, regardless of whether you’re running iTunes or HandBrake. And it’s a great time to be an overclocking enthusiast, with affordable 45nm processors easily scaling in excess of 4 GHz and upcoming 32nm models hitting 4.5 GHz without much effort here in the lab.

Of course, there’s a big caveat or two tied to altering default settings. First of all, there’s the risk involved. Gunning for 4 GHz using 1.45V isn’t particularly ambitious (even using air cooling), but should you fry your CPU, it won’t be covered by warranty. Moreover, power consumption increases significantly under load when you augment clock rate and voltage. Fortunately, the motherboard we’re using here correctly scales down power and clock rate during idle periods.

Finally, it’s worth reminding our readers that, if you’re a gamer, there’s little reason to sink your resources into an expensive processor. From the sub-$200 Core i5-750 up to the $300 Core i7-860 (and beyond—we’ve seen this phenomenon over and over), you’re going to realize the same frame rates at most resolutions unless you buy very expensive graphics card configurations.

Chris Angelini is an Editor Emeritus at Tom's Hardware US. He edits hardware reviews and covers high-profile CPU and GPU launches.