Skip to main content

Experiment: Does Intel’s Turbo Boost Trump Overclocking?

Benchmark Results: Productivity

Our Adobe Photoshop CS4 benchmark consists of several threaded filters applied to a .tif image. It’s little surprise, then, that Turbo Boost has a minimal effect here. Hyper-Threading doesn’t seem to do much either.

What really does help boost performance in Photoshop CS4 is clock rate. The Core i7-860 at 2.8 GHz does a bit better than the Core i5-750 at 2.66 GHz, while Turbo Boost enabled adds 133 MHz to both chips. Then, at 4 GHz, they both turn in comparable numbers, which are significantly quicker than the non-overclocked scores.

We’ve been perplexed by the behavior of AVG 9, which hasn’t scaled well at all since we upgraded from AVG 8.5. However, simply running the task manager as this test executes tells the tale. As the scanner runs, it’s only consuming, at most, 10% of the processor’s resources. We tested across dual-core chips and Atom-based platforms—performance does slow down as you take execution cores away and drop clock rate. However, the Core i5-750 and Core i7-860 are similar enough that their performances in AVG 9 are virtually identical.

3ds Max 2010 enjoys a benefit from both Hyper-Threading and Turbo Boost technology. Overclocking remains the best way to maximize your experience in this title though. The Core i5-750 even enjoys a slight advantage at 4 GHz via its 200 MHz BCLK, which is 10 MHz higher than the i7-860’s 190 MHz setting.

Known to be threaded (but clearly not optimized for Hyper-Threading), WinRAR gets a minimal speed-up from Turbo Boost technology since all four of its cores are active. Turning Turbo Boost off completely backs the speed of each CPU down by 133 MHz when they’re fully utilized, which is why Turbo Boost appears to help somewhat.

When both chips are dialed in to 4 GHz, though, performance is comparable (and significantly faster than stock settings).

Another test we’ve added based on popular demand, 7zip is also freely available and well-optimized for today’s processor architectures.

As we can see, the compression speed (in KB/s) scales not only to clock rate, but also available cores. In fact, the Core i5-750 at 4 GHz isn’t even able to match the Core i7-860 at 2.8 GHz with Turbo Boost disabled.

Because this title is well-threaded, Turbo adds very little to the bottom-line. Hyper-Threading adds quite a bit of performance, and overclocking once again shows a serious win.

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