Power consumption and efficiency
Well, why wait, right? Let's take a look at Ivy's finest attribute, her increased power efficiency, in our first-real world test. Note that we've measured total system power consumption at the wall socket, so our results are taking account of the whole platform picture.
Our workload for this test was encoding a video with x264, based on a command ripped straight from the x264 benchmark you'll see later. This encoding job is a two-pass process. The first pass is lightly multithread and will give us the chance to see how power consumption looks when mechanisms like SpeedStep and core power gating are is use. The second pass is more widely multithreaded.
There's the story for Ivy Bridge, right there in those two plots, if you read 'em right. The 3770K draws less power than the 2600K, yet it finishes the job about five seconds faster. Let's see what specifics we can derive from these data.
Ivy's power draw at idle is very similar to Sandy's, despite Ivy's ~50% higher transistor count. Of the other solutions, only AMD's A8-3850 comes close.
We measured the 2600K's peak power draw at 17W higher than the 3770K's. The gap between their TDP ratings? 18W. With Turbo Boost's dynamic power management, both chips are likely reaching something close to their peaks and remaining there. And Ivy is clearly more efficient.
Here's a look at energy consumed over our entire test period, where both active and idle time are taken into account. During the entire span, the 3770K's combination of low peak power, quick execution, and relatively low idle power allows it to take the top spot.
Now we're looking at just the energy consumed while the video was being encoded. Here, the 3770K's lead on the other processors grows. Thanks to the benefits of Intel's 22-nm process and some modest improvements in per-clock performance, Ivy Bridge is the most energy-efficient chip of this bunch by a considerable margin.