[uudecode]

This is common not just in Intel chips but in all electronics.

Instead of making several versions, each with with more features, only one version is made that contains all possible features.

Whether they are turned on or off is what correlates with the "model" and the price.

Turn features off and sell as "basic" model. Turn features on and sell as "pro" model.

In this story, turning on features correlates with whether the customer has deep pockets and consistently buys in large quantities.

[akiselev]

This is also important for the economy of making chips at scale. Since silicon fab is very precise a single wafer can have from dozens to thousands of errors, ranging from failed doping to entire scratches on the surface. Making monolithic all in one chips allows you work around those errors instead of throwing out that part of the wafer.

Say you're making an i7 and half the chips on the wafer have scratches on one or two of the cores. Instead of throwing out half the wafer (doubling the per CPU price) you just disable the damaged cores and sell them as i5s instead.

[kabouseng]

Yeah sure but there is a tradeoff, making larger (more fully featured) chips also reduces your yield as the chance a chip has a defect is dependant on it's size / surface area.