Without knowing exactly which trading programs you're planning on using I couldn't say if they'd take advantage of a quad core or not. Quickbooks and Microsoft Office would run just fine on a dual core, but if you have the option of going with an i7 quad core I cant think of any reason why you shouldn't, beyond the slightly higher power that a quad core i7 would need over a dual core i5/i7. As C17 mentioned, not all i7's are quad cores so make sure to research out if the laptop you're looking at is a dual or quad core. As for 4th gen vs 5th gen, 5th gen are supposed to have much better power savings and so if budget allows I'd say go for that.