Clarkdale's Efficiency: Core i5-661 Versus Core 2, Athlon II, And Phenom II

Intel’s new Core i3 and i5 dual-cores arrived with a bang, offering more performance than the Core 2 Duo family they’ll eventually replace. The integration of a graphics unit into the processor may be a key enabler to maximizing efficiency of LGA 1156 systems, but just how much more efficient is Intel’s new platform? We grabbed an H55-based motherboard and the Core i5-661 (centering on the Clarkdale core) to compare with Intel's Core 2 Duo E8600 and G45 chipset. We also compared against an AMD 785G-based system running both an efficient Athlon II X2 240e and the fast Phenom II X2 550 Black Edition.

Intel is working towards greater integration. The H55/H57/Q57 platforms with Core i3/i5 Clarkfield CPUs now move the graphics unit and the memory controller out of the chipset and into the processor. The memory controller was already relocated on the Core i7 (Bloomfield) in the high-end market and Core i5/i7 (Lynnfield) in the upper-mainstream. The low-end Atom platform also follows with next-generation Pine Trail, which also transitions the platform from three to only two chips. Today, though, Intel is focused on the lucrative mainstream desktop and mobile segments. For purposes here, we’ll concentrate on the desktop side.

Our technology launch article by Chris Angelini already covered all aspects of the new processors, such as the integrated HD Graphics unit, Turbo Boost in the context of integrated graphics, the additional instructions to accelerate AES encryption and decryption, and specifications and clock speeds. Now it’s time to have a closer look at system power consumption and efficiency in terms of performance per watt. Intel now has its 32nm silver bullet, which should make the dual-cores much more efficient at base clock rates. Most people expected Intel’s new dual-cores to dominate in efficiency, but we wanted to have a close look at the power characteristics.