Efficiency Explored: Core i7-980X Versus Core i7-975


It has to be said that Intel’s 32nm production capabilities seem to be working really well. The Clarkdale and Gulftown designs centering on this new manufacturing process continue to impress us with regard to efficiency. The Core i5 dual-cores already proved that high clock speeds and low power consumption can go hand in hand today, and the new Core i7-980X six-core enthusiast CPU for Intel's LGA 1366 interface introduces the most advanced manufacturing technology into the high-end. The next logical step is its induction into the professional world within the Xeon product line.

Our initial skepticism clearly was out of place. Not only does Gulftown deliver in terms of performance—there is no faster processor today—but it also beats the previous flagship Core i7-975 Extreme Edition in efficiency and performance per watt. We didn’t include AMD offerings here, as the differences in performance, efficiency, pricing, and value are way too large. You can buy five of AMD’s Phenom II X4 flagship for the cost of one Core i7 Extreme Edition.

Gulftown is at least as fast as Bloomfield in every workload, and outperforms it once more than four threads are involved. We will be looking at the impact of Hyper-Threading in a separate article, but if you intend to spend $1,000 just on a CPU, there's every reason to spend it on the latest six-core offering.

In addition to being fast, Gulftown is actually lower on idle power, lower on peak power, and lower on average power when working on our efficiency workload. The addition of Intel’s AES new instructions to accelerate encryption and decryption are a welcome bonus, as well. However, higher Turbo Boost frequencies would certainly help to further improve the processor’s efficiency on conventional applications that run on only one or two cores.

More Turbo Boost Please!

It would be more than appropriate for such a potent processor with the power handling capabilities of this one to be more aggressive on Turbo Boost. Right now, Core i7-980X doesn’t go faster than 3.60 GHz on one cores, although we already found that the 32nm silicon is rock solid at up to 4.13 GHz base speed (with six active cores) and 4.4 GHz with Turbo Boost. At $1,000, I believe a 4 GHz Turbo Boost speed for one or two active cores could be justified, as it's theoretically possible for a dual-core Core i5 to overtake the i7-980X on a single-threaded apps at its 3.73 GHz Turbo'd frequency.