Performance Features and Overclocking

In this section, we examine the performance features and overclocking potential of the Core i7-870. As i mentioned earlier, all of the Lynnfield processors launched this week have the advantage of Intel's revised Turbo Boost Technology. As this is an i7-800 series chip, it also has Hyper-Threading enabled. Both of these technologies are enabled by default and were used in all of our benchmarking so far. However, to illustrate impact each has on overall performance, I ran a selection of the benchmarks with both technologies disabled. To further isolate the two, I also ran the benchmarks with only Turbo Boost enabled and only Hyper-Threading enabled. You'll find the results in the charts below.

In addition to the included performance features, the charts also reflect the results of manual overclocking. As we saw with the i5-750, one of the first decisions you'll have to make is whether to enable or disabled Turbo Boost. With it enabled, I was able to increase the bus speed to 160 MHz for a base clock speed of 3.52 GHz and a maximum turbo clock speed of 4.32 GHz. This is roughly the same result I achieved with the i5-750. Disabling Turbo Boost would most likely net a much higher base clock speed for all four cores, but at the cost high single-threaded performance. To stay consistent with previous, I decided to run the benchmarks at the highest Turbo Boost clock speed.

Looking at the EVEREST integer results, we find that in the PhotoWorxx and AES benchmarks, Turbo Boost yielded a higher performance increase than Hyper-Threading compared to the baseline. Of course, enabling both results in the best scores at stock speeds. As is to be expected, though, overclocking had an even more significant effect on performance.

Moving on to Crysis, we find that once again Turbo Boost has more of an impact on performance than Hyper-Threading. Clearly, clock speed is more valuable in Crysis than the jump from four processing threads to eight. Of course, it does have some effect and when both technologies are combined we observe a synergistic effect. It's also worth pointing out that neither technology, nor our attempts at overclocking altered the Core i7-870's performance in the last two tests. No increase to clock speed or processing threads can remove the limitation of our Radeon D 4850.

CINEBENCH finally give the i7-870's Hyper-Threading time to shine. In the multi-threaded benchmark, it's clear that the extra threads help out quite a bit. Quite obviously, however, it has no effect in the single-threaded benchmark. It's here that Turbo Boost comes out on top. Not surprisingly, enabling both technologies and overclocking produces an even more significant increase in performance.

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