The IBM-Cell in the PS3 was a different approach to the same problem. The Cell was specified as 7-SPUs and 1-CPU, but in actuality... the manufacturing process made 8-SPUs and 1-CPU.
IBM assumed that one of the SPUs would fail during manufacturing, so they only promised to deliver 7 of them per PS3.
You can literally see the 8 SPUs: https://upload.wikimedia.org/wikipedia/commons/e/e0/Cell-Pro...
There's lots of ways to approach the problem. Manufacturing is an imperfect process: not everything is made identically. So the manufacturers have to figure out how to test for differences and... if necessary... sell the same "manufactured" chip in different bins.
Phenom.
https://en.wikipedia.org/wiki/AMD_Phenom
https://en.wikipedia.org/wiki/Phenom_II
Not all the hardware of Cell on PS3 was available if you run the official Linux port. Which was later blatantly removed.
As a hypothetical example (I'm not 100% sure if this is how Intel does things), and i5 could just be an i7 except it couldn't handle the higher clock rate. So instead of throwing away a chip that's limited in clock... Intel will sell the chip as an i5.
Or perhaps in another chip, the hyperthreading portion got borked because of a piece of dust landed in the lithography. So instead of selling it as an i7, the hyperthreading portion is fused off and the chip is sold as an i5.