I5 2450M with a 7200 RPM hd or a i7 2670QM with a 5400 RPM hd

I have around $500 to spend on a laptop that I will be using to record music. This is a problem, as I know nothing about computers. After several days of research I've narrowed it down to two laptops that seem to be the best I'll be able to get for my meager amount of cash (for a computer anyway).

1. a Dell Inspiron 14z with a i5 2450M,500GB SATA II Hard Drive (7200 RPM) and 6GB DDR3 SDRAM

2. a Dell Inspiron 15R with i7 2670QM, 750GB 5400 HD and 6GB DDR3 SDRAM

I want to direct record guitar/bass and some vocals. I can't see myself using more than 8 tracks (if that). I want to use some VSTs for guitar effects and I will be using Reaper.

During my several days of research (which brought me to this sight many times) I gleaned that HD speed kind of matters? I'm not sure if to pushes one of these options over the edge or not? Which would provide usable latency with an amp modeler and an effect or two?

Thanks