[Solved] Quad core i7 vs dual core i5 (looking for advice for new laptop)

Hey all,
I'm a student headed for college next year and i'm looking for an upgrade from my current xps m1330. One of the laptops i'm currently looking at (ENVY 14) has the option to choose between an i5-580M Dual Core Processor (2.66GHz, 3MB L3 Cache) with boost up to 3.33GHz and an i7-740QM Quad Core processor (1.73GHz, 6MB L3 Cache) with boost up to 2.93 GHz. If the i5 is chosen, the laptop comes with a 1GB DDR3 ATI Mobility Radeon HD 5650 switchable graphics [HDMI]. If the i7 is chosen, the laptop comes with the same card but without the switchable graphics capability.

I will use this laptop primarily for school (which will include MATLAB and other engineering based programs), although I will also probably use it for the occasional game of League of Legends (if any of you are familiar) and some music/video editing.

I'm definitely looking for something with a significant amount of power, but I don't want to sacrifice too much battery life just for a slightly faster processor.

Which processor would you guys recommend for my situation?
Any help is greatly appreciated!

Had a similar problem faster dual or slow quad, I went with the Quad, in my case i7-720.

Using it for day to day office work and internet, no difference from a faster dual, it all depends on how you configure the Windows environment.

When number crunching needed, it has the horse power, best decision I made was to go quad.

In your case, would rather loose 400mhz in speed than 3MB in cache, especially for the apps you plan on using.