Quick background: I'm looking for a new laptop - my old one which had a Core i7 (and died after a year) didn't overwhelm me with its speed, so I figure I shouldn't get anything worse than an i7 in this one. I then noticed that there were many different "versions" of the Core i7 (e.g. 4700MQ, 3517U, etc.) - I had no idea, and really thought there was just one Core i3, one Core i5, and one Core i7.
I found cpubenchmark.net which has a comprehensive list of many processors. They assign a "Passmark CPU Mark" to each of them. For example, the 3517U's value is 3738, while the 4700MQ's value is 7982. My question: what's the real difference between these two? Is this rating linear (e.g. is the 4700MQ more than twice as fast as the 3517U?)? If I have two otherwise identical machines, how much of a difference will I notice between the two processors?