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.
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.
Dan Luu wrote that Intel's cache allocation tech particularly helped Google, so they could run multiple workloads on one machine without totally trashing the larger caches at every context switch: http://danluu.com/intel-cat/
The Xeon D chips, which provide cheap low-clocked big cores and integrated NICs for small servers, were requested by Facebook: https://code.facebook.com/posts/1711485769063510/facebook-s-...
Someone who follows server chips (maybe AnandTech?) called Xeon D's one of Intel's coolest product lines to come out recently. They're also arguably a smart way for Intel to seal off the lower end of the market against approaches with tons of cheap ARM or AMD cores.
[1] zeptobars.com/en/read/open-microchip-asic-what-inside-II-msp430-pic-z80
A lot of Intel's chips are recycled binned Xeons. They've almost completely stopped making desktop processors.
The I7s you buy are usually failed Xeon chips. To my knowledge Intel currently only fabs laptop and server chips.
There were only a few xeons that were made into desktop processors and they ended up as i3's there were a few of those that supported ECC.
The 'E' edition CPU's can potentially be xeons but then they aren't failed ones but highly cherry picked ones as they boot and overclock very high.
In this case Intel is building certain accelerators for some of its customers, and enabling it only for them before shipping it out. I don't think any of these cores contain trade secrets, rather specific functions they've requested which helps accelerate their stack.
Imagine the potential conversation between Intel and the NSA:
NSA: Please backdoor your RNG for us. Intel: We're making xx billions of this chip. What happens if someone finds out and we have to recall the chip. Are you paying us the xx billions back then? NSA: ...
It is fairly unlikely the NSA could afford Intel.
Also, remember that it's easier to do if you disguise it as a coding flaw. It wasn't a backdoor: just one among many flaws accidentally hitting our systems. Wouldn't cost any market share.
NSA: Please backdoor all sorts of stuf Intel: ok
Security Researcher: these chips have backdoors
Intel: Maybe they do, what are you going to do about it?
Basically binning for different market segments.
Powering all that useless (to us) real estate must have profound consequences on our energy budget
The most common example I can think of is BCH coprocessing, which most modern application processors use for verifying data stored in embedded Flash.
https://en.wikipedia.org/wiki/Application-specific_integrate...
This is something I've never heard of before. Anyone have some insight into this? Is it a relatively recent phenomenon?