Medium sized i7 laptop

http://www.dell.com/us/en/dfb/notebooks/precn_m/cp.aspx...

They are refurbs, but nice hardware on the cheap... just dont buy the one im looking at for work lol.

http://www.newegg.com/Product/ProductList.aspx?Submit=E...

take your pick, just make sure to sat away from the Core i7-6xxm series as they are dual cores, you want 7xx or higher

How is the difference performance-wise between the i7-6xxm (dual core) and the i7 7xx (quad core)? is the performance difference large? and would the battery life be significantly better with the i7 dual core? i heard that when some of the cores arent needed they power off so even the quad core should not use too much power if its like idling or just surfing the web am i correct?

so mainly what i want to know between the i7 dual and quad core is performance and battery difference. thanks  

if you wanted a dual core, just rad an i5 in the laptop (as the i7-620 will perform about the same), if you want a quad core grad the i7-7xx (or higher) series

there is a difference in power consumption as the quads are 45w TDP and the duals are 35w RDP, but there is a difference in performance where in 1 or 2 threaded programs they will be about the same but for more threads the i7-7xx will be faster