An i5 typically lacks Hyper-Threading, but it has more cores (currently, six, rather than four) than Core i3. The i5 parts also generally have higher clock speeds, a larger cache, and can handle more memory. The integrated graphics are also a bit better. You see new Core i5 processors with Hyper-Threading on laptops, but not desktops.

Core i3 chips are good for everyday computing. If you run web browsers, Office applications, media software and low-end games, one of these will be ample – but don’t expect a Core i3 part to handle content creation, serious photo-editing or video work. It’ll slow you down tougher games too. Core i5 parts are better for most of these tasks.