The winner of the first Windows 8 vs. Windows 7 boot performance measuring contest is clear, and I doubt that we’ll ever see a comeback from Windows Vista’s successor in future comparisons.

An important aspect of Windows 8’s evolution is the fine tuning of the start-up process. Technologies such as solid state drive (SSDs) and Unified Extensible Firmware Interface (UEFI) aside, the next iteration of Windows comes with optimizations which will let Windows 7 in its boot dust.

Windows 8 vs. Windows 7 ? Boot Performance Comparison - Softpedia

and

Bink.nu | Wow, Windows 8 boots under 10 seconds! - Bink.nu