Official comment
Not all computers are equal -- you could find that a 5 year old computer running an i3 processor that performs better than a 2 year old computer with an i5. Sometimes it's the hardware itself (like the USB bridge, memory bus, etc), other times it's the fact there's software or system processes running in the background that hamper software performance.
What you will typically find is the higher performance processors will give you a longer life; my 2012 MacBook Pro with an i7 processor is still capable of running new OS's and software with decent speed, but if it were an i5, it might not have the same abilities at the same age.
While the minimum requirements are a Core2Duo / i3, that's the minimum. Using anything above that is recommended.