I had the first nexus 7, and many of my friends have the 2nd gen one, the extra price for the second gen is jusitified by its better features, it runs games so much better than the 1st gen.
I've also used battery doctor, it works wonders and perhaps clean master, it shuts own background apps to free more ram. thats for android on ios, gba4ios is pretty good, and will run gba games smoothly.
There are currently no 8 core laptop cpus, perhaps 4-core would be better, try and find one, maybe a toshiba, with a gig or two of graphics. 8 core is not even optimized yet, so there would be no reason to buy one anyway.