I use iStat Menus but there are a bunch out there, some free, some not. iStat looks the best in my opinion.What Air do you have? I am using a 2010 1.6ghz C2D, 4GB of RAM, 128GB SSD. I have a 15" 2012 2.3ghz quad with 8GB of RAM and an Intel 330 240GB and even though it's faster by a huge margin, since I've resurrected this machine from liquid damage I've used it exclusively because the size/weight and screen sharpness vs the MBP.
11/2/13 at 5:11pm