The architecture of this duo core processor is [1]

Correct (the one which seems to work) cflags should be
a
In the make.conf set the following

CHOST="i686-pc-linux-gnu"
CFLAGS="-march=prescott -O2 -pipe -fomit-frame-pointer"
MAKEOPTS="-j3"

a

Processor Brand: Intel
Processor Class: Core Duo Processor
Processor Number: T2400
Processor Speed: 1.83 GHz
Bus Speed: 667 MHz
Mobile Technology: Centrino
L2 Cache Size: 2 MB
System Chipset: Intel 945GM Express
Memory Speed: PC2-4200 (533MHz)
Memory Technology: DDR2-SDRAM
Installed Memory: 1 GB
Maximum Memory: 2 GB
Hard Drive Capacity: 100 GB
Drive Controllers: SATA-150
Rotational Speed: 5400 RPM
Additional Drives: DL DVD+/-RW
Sound Support: Digital Audio (16-bit)
Video Chipset Brand: NVIDIA
Video Chipset: GeForce Go 7400
Installed Video Memory: 128 MB
Resolution: 1280 x 800
Display Size: 13.3 in
Display Type: Active Matrix LCD (TFT)
Port Connectors: Audio Interface: Microphone jack, Headphone jack
Graphics Interface: VGA out with Smart Display Sensor
1 VGA output
1 i.LINK connector (IEEE 1394) (4 pin)
2 USB 2.0 ports
Port replicator connector

Card Slots: Memory Stick Duo
ExpressCard/34
(1) Type II / Type I CardBus
Network Support: Ethernet (10/100 Mbps)
Wireless Protocol: 802.11a
802.11b
802.11g
Modem Speed: 56 Kbps
Input Devices: Keyboard
Touchpad
Battery Life (average): up to 6.0 Hours
Number of Batteries: 1
Installed Operating System: Windows XP Professional
Included Software: Anti-Virus and Recovery Software:
Norton Internet Security 60-Day Subscription – Norton AntiVirus, Norton Personal Firewall, Norton Privacy Control, Norton AntiSpam, Norton Parental Control
TrendMicro Anti-Spyware 30-Day Trial
Sony VAIO Security Center
Sony VAIO Update software
Sony VAIO Recovery Wizard software
Sony VAIO Support Central
Supplied Applications:
Adobe Photoshop Album Starter Edition
Intuit Quicken 2005 New User Edition (previous Quicken users may require additional upgrade)
InterVideo WinDVD
Microsoft Works 8.5 – Word Processing, Spreadsheet, Calendar, Scheduling, Contact Management, and Database
Roxio DigitalMedia SE
Sony Original Software:
Click to DVD – DVD Creation
DVGate Plus – Digital Video
SonicStage Mastering Studio – Audio Mastering and Remastering
SonicStage – Digital Music
VAIO Media – Network File Sharing
Image Converter – PSP Transfer
In the Box: Sony VAIO SZ120P/B Notebook
Standard Lithium-ion battery (VGP-BPS2C)
AC adapter (VGP-AC19V10)
Memory Card Adapter (VGP-MCA20)
Power Cord
Height: 1.5 in
Width: 12.5 in
Depth: 9.3 in
Weight: 4.1 lbs

a
Well, the power consumption comparisons of intel core Duo processors are as follows (grabbed from intel website)

Intel® Centrino® Duo mobile technology Featuring
Intel® Core™ Duo processor


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Intel® Pentium® Processor Extreme Edition Intel® Pentium® Processor Extreme Edition
Processor
Number
Architecture Cache Clock
Speed
Front
Side
Bus
Power Dual-core Intel®
VT±
Enhanced
Intel
SpeedStep®
Technology
Execute
Disable Bit°
T2700 65 nm 2 MB L2 2.33 GHz 667 MHz 31W
T2600 65 nm 2 MB L2 2.16 GHz 667 MHz 31W
T2500 65 nm 2 MB L2 2 GHz 667 MHz 31W
T2400 65 nm 2 MB L2 1.83 GHz 667 MHz 31W
T2300 65 nm 2 MB L2 1.66 GHz 667 MHz 31W
T2300E 65 nm 2 MB L2 1.66 GHz 667 MHz 31W

Intel® Centrino® Duo mobile technology Featuring
Intel® Core™ Duo processor Low Voltage


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–>

Intel® Pentium® Processor Extreme Edition Intel® Pentium® Processor Extreme Edition
Processor
Number
Architecture Cache Clock
Speed
Front
Side
Bus
Power Dual-core Intel®
VT±
Enhanced
Intel
SpeedStep®
Technology
Execute
Disable Bit°
L2500 65 nm 2MB L2 1.83 GHz 667 MHz 15W
L2400 65 nm 2MB L2 1.66 GHz 667 MHz 15W
L2300 65 nm 2MB L2 1.50 GHz 667 MHz 15W

Intel® Centrino® Duo mobile technology Featuring
Intel® Core™ Duo processor Ultra Low Voltage


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Intel® Pentium® Processor Extreme Edition