Benchmark Results: iTunes
Our single-threaded iTunes workload gives us a nice contrast to Photoshop and WinRAR, since it allows each CPU to hit its highest Turbo Boost frequency and strut the virtues of its respective architecture.
Because it accelerates to a higher clock rate and enjoys better instruction-per-cycle throughput, the Core i5-3427U in our second-gen Ultrabook cruises past the Core i5-2467M in our older machine. Both 45 W parts turn in even more impressive results, though the Core i7-2820QM isn't that much faster than the Ivy Bridge-based part under the microscope today.
Because iTunes' AAC conversion only uses one thread at a time, we can't tax any of these machines using it. The Ivy Bridge-based Core i7-3720QM spins up a single core, but it exploits as much available TDP as possible to reach 3.6 GHz. In comparison, last-generation's Core i7-2820QM touches 3.4 GHz. But because its power consumption spikes slightly higher, it isn't as efficient.
The 17 W Core i5s exhibit similar CPU utilization, but the Ivy Bridge-based -3427U demonstrates a power consumption advantage. A peak Turbo Boost clock of 2.8 GHz allows the newer chip to get its job faster within the same power envelope as the older model, which tops out at 2.3 GHz.