Core i5 or Core i7—does your computer need the extra juice?

arstechnica by Andrew Cunningham

Should new Mac and PC buyers spend the extra money for that lucky number seven?

Apple unleashed a pile of new Mac hardware on its users Tuesday: new 13" Retina MacBook Pros and Mac Minis using Intel's newest Ivy Bridge processors are available for shipping now, while substantially redesigned iMacs begin shipping in November and December. If you like to upgrade when things are new, now is the time to strike.

Any new computer is an investment, though, and you'll want to make sure that what you're buying will last for as long as possible. For each of the new Macs Apple began selling yesterday, the company offers a $200 upgrade option that will turn your Core i5 processor into a Core i7 processor (and while it hasn't started selling the new iMacs yet, those computers should have a similar upgrade path). If you're in the market for a new Mac (or any computer, really), do these CPU upgrades give you a good bang for your upgrade buck?

What's in a number? Well, it depends...

So what's the difference between a Core i5 and a Core i7? Well, thanks to Intel, the answer isn't simple.

The iMacs use desktop-class processors rather than the mobile processors used by the MacBook Pros and Mac Minis, which makes things a bit easier: a Core i7 upgrade will get you more processor cache, more clock speed, and Hyper-threading. read more...