Does Turbo Boost Help Or Hurt Core i5/i7's Power Efficiency?

Test Setup

System Hardware
Performance Benchmarks
Motherboard (LGA 1156)
Intel DP55KG (Rev. 1.0)
Chipset: Intel P55
BIOS:   KGIBX10J.86A.3456 (08/22/2009)
Motherboard (LGA 775)
MSI P45D3 Neo (Rev. 1.0)
Chipset: Intel P45, ICH10R
BIOS: 4.2 (02/18/2009)
CPU Intel I
Intel Core i5-750 (45nm, 2.66 GHz, 4 x 256KB L2 and 8MB L3 Cache, TDP 95W, Rev. B1)
CPU Intel II
Intel Core i7-870 (45nm, 2.93 GHz, 4 x 256KB L2 and 8MB L3 Cache, TDP 95W, Rev. B1)
Intel Core 2 Quad Q8200S (45nm, 2.33 GHz, 4MB L2 Cache, TDP 65W, Rev. R0)
CPU Intel IV
Intel Core 2 Quad Q9550S (45nm, 2.83 GHz, 12MB L2 Cache, TDP 65W, Rev. E0)
CPU Intel V
Intel Core 2 Extreme Q9650 (45nm, 3.00 GHz, 12MB L2 Cache, TDP 130W, Rev. C0)
RAM DDR3 (Dual)
2 x 2GB DDR3-1600 (Corsair CM3X2G1600C9DHX)
2 x 1GB DDR3-2000 (OCZ OCZ3P2000EB1G)
Zotac Geforce GTX 260²
GPU: Geforce GTX 260 (576 MHz), Graphics RAM: 896MB DDR3 (1998 MHz), Stream Processors: 216, Shader Clock: 1242 MHz
Hard Drive
Western Digital VelociRaptor, 300GB (WD3000HLFS)
10,000 RPM, SATA/300, 16MB Cache
Blu-Ray Drive
Power Supply
PC Power & Cooling, Silencer 750EPS12V 750W
System Software and Drivers
Operating System
Windows Vista Enterprise Version 6.0 x64
Service Pack 2 (Build 6000)
Drivers and Settings
AMD Chipset Drivers
Catalyst Control Center 9.4
Intel Chipset Drivers
Chipset Installation Utility Ver.
Intel Storage Drivers
Matrix Storage Drivers Ver.

Intel Core i7-870Intel Core i7-870

Intel’s DP55KG LGA 1156 platformIntel’s DP55KG LGA 1156 platform