Four Cores For The Power Consumption Of Two

Intel’s Core i7 processor family has been available for a few months now, but despite being the undisputed performance champion, it is not yet ready for the true mainstream. Processors, and especially motherboards, are still too expensive; and the existing models deliver their impressive performance at equivalently impressive power consumption figures. But users looking for the best balance between performance and efficiency have an interesting new option now: Intel has released its first 45 nm Core 2 Quad processors that stay below a specified power consumption of 65 W--the Core 2 Quad S series.

Bringing Power Consumption Down

Although processors have reduced their power consumption by more than 50% since the good old Pentium 4 powerhouse, the addition of processing cores typically increases power consumption, at least during high load conditions. While we believe it is absolutely acceptable to live with a certain power requirement for high performance parts, everything should be done to keep power consumption reasonable while the processor is idle or running at a low load level.

Features Versus Technology

All modern processors implement power saving features. Cool’n’Quiet by AMD and SpeedStep from Intel allow the operating system to lower the clock speed and processor voltage to decrease power consumption. In addition, processors are capable of switching into halt states, which means they may interrupt execution for very short periods of time. Finally, some sections of modern processors can be completely shut down when they are not needed; this has traditionally applied to caches, but is increasingly being used for processor cores as well.

Manufacturing technology keeps improving, and processor manufacturers use these advances to introduce minor improvements to their products. Our article AMD’s Athlon Stepping Improvements, which we published in March of 2008, is a great example. We took four different processors that are all named “Athlon 64 X2 5000+” but are all based on different silicon steppings, and compared them.

Improvements at the silicon level can be used to accelerate processors within particular thermal envelopes, or to decrease processor power. Intel did the latter here, introducing additional Core 2 Quad processors named the Q8200S, Q9400S, and Q9550S. These are as fast as the regular versions, but they don’t require up to 95 W of power. All three models stay below the mainstream thermal envelope of 65 W, which finally makes Intel quad cores interesting for low-power systems.

Check prices for Intel's Core 2 Quad Q9400S