Lower power usage for Barton

[herbocharged]

http://www.amdzone.com/articleview.cfm?articleid=1240&page=2

How did AMD manage to reduce the power while adding 17million transistors. Barton has the same voltage as T-bred but a lower Icc typ. The frequecy is 67Mhz lower, but that shouldn't make that much of a difference.

Athlon XP model number: 3000+
Cache Size: L1 - 128KB and L2 - 512KB = 640KB Total Cache
Frequency / Bus / Multiplier: 2.167GHz / 333FSB / 13.0x multiplier
Infrastructure Support: Socket A motherboards
Fab location: AMD's Fab 30 wafer fabrication facility in Dresden, Germany
Process Technology: 0.13 micron copper process technology
Die Size: 101mm2
Approximate Transistor count: 54.3 million
Nominal Voltage: 1.65v
Max Die Temp: 85 degrees Celsius
Typical Thermal Power: 58.4 W
Max Thermal Power: 74.3 W
Icc Typical (low power state): 7.2 A
Icc Typical (working state): 35.4 A
Icc (processor current) Max: 45.0 A

Athlon XP model number: 2800+
Operating Frequency: 2.25GHz/333FSB (2.17GHz/333FSB)
Manufactured: AMD's Fab 30 wafer fabrication facility in Dresden, Germany.
Process Technology: 0.13 micron copper process technology / Thoroughbred rev-B
Cache Size: L1 - 128KB and L2 - 256KB = 384KB Total Cache
Nominal Voltage: 1.65v
Die Size 84mm2
Transistor count: Approx: 37.6 million
Infrastructure: Socket A
Max Die Temp: 85 degrees Celsius
Typical Thermal Power: 64.0 W (62.0 W)
Max Thermal Power: 74.3 W (68.3 W)
Icc Typical (low power state): 5.4 A (5.9 A)
Icc Typical (working state): 38.8 A (37.6 A)
Icc (processor current) Max: 44.9 A (41.4 A)