Which one is better used or new

[silenty]

hello guyes

i was going to buy a second hand core 2 due e7400 instead of a new e5700 dual core cause i knew that the core 2 due is better than dual core in everything
but today i saw a comparsion between them and some one on an arabic forum on my country told me that the e 5700 is better because its allready 3.1 gb and its better for OC and he gave me this link to this comparsion
http://www.cpu-world.com/Compare/387/Intel_Core_2_Duo_E7400_vs_Intel_Pentium_Dual-Core_E5700.html

actually i cant understand anything of this comparsion because i am a regular user not a professional
so could any one tell me on a simple way which one is better (for gaming )

excuse my poor language

 

[silenty]

the current tech costs a lot here in my country
starts from 200$ to 500$
and my salary is around 300$ per month