I'm going to buy my son a laptop for him to use at collage. And i'm totally lost, I'v never bought a laptop only desktops. What's the differance between the T4300, T6600 Intels and the AMD duel cores. With the blackfriday deals of 500$ or below its time, but wich one will be faster? Heres a few I found. So T4300,T6600 or AMD and wich AMD duel core?
To make a long story short, the T6600 will outperform the t4300, even though the t4300 may have a high clock speed, as it has more cache, etc... I'd stick with the Intel mobile chips over the AMD's, as they tend to run cooler and last longer in my experience. Other may disagree though.
I think the L505D is a pretty good choice out of the 3. Unless your son is just going to leave the laptop on his desk, the 17" laptops are a bit hefty to carry around... say to the library or to a study group. The newer AMD cpu should be similar to the Intel offerings and faster than the older generation QL series in the other laptop you posted. Although still not that powerful, the AMD integrated graphics is superior to the Intel.