Which processor is better? I7 640M or T9600 Duo

[Mehrdad1356]

Hello,
I have a M4400 Dell Precision laptop and want to buy another M4500 Precision. The old one has Intel(R) Core(TM)2 Duo CPU T9600 @ 2.80GHz, 2801 Mhz, 2 Core(s), 2 Logical Processor(s)and I think 6MB Cache but the new one is Intel® Core™ i7-640M Processor
(4M Cache, 2.80 GHz)

Would you tell me which one is faster and more efficient for computation and complicated 3D CAD applications?
Thank you for all answers

 

[LePhuronn]

The i7 by a long way