Many hardware enthusiasts know that I3 I5 I7 is virtually the same in every update process. But why are the performance and quality of these CPU different? Is it difficult to make manufacturing between them? This article will give you a scientific knowledge of this, we should know the basic common sense!
Because there is one thing called good yield!
Let's start with the semiconductor manufacturing process:
First of all, the basic material is monocrystallie silicon, which basically melts the polysilicon, throws a crystal inside it, lets it crystallize, and pulls it out, probably like this. (pictures come from the web):
Then cut into slices, right! Like cut sushi! But it's very thin. Here's the picture (from the network):
Then, by exposing and etching, many structures are engraved on it, like this (pictures from the network):
Then cut it into pieces and cut it (pictures from the Internet):
Package sold to you (pictures from the network):
But the real situation is not so good! The real structure is like this (pictures come from the web):
Does it look like it has a lot of burrs? (Here right should be flat gate manufactured and not perfect vertical) that is to say, the etching process is not perfect, there may be some of the attached moment opened, many of the places where no moment open moment. Especially, according to our intuition (in fact it is so), in the wafer edge etching quality is relatively poor, the center will be better.
That's why the chips are done and tested.
There are some small problems, such as a trench, both sides should be insulated, but this ditch moment is quite narrow, a high frequency breakdown run, so they can only run a relatively low frequency. Some of them were simply broken, so the piece would not work.
You know, I3 and i7 are the same in architecture, but they run at different frequencies. Well, the results of those tests are good. They encapsulate a high frequency, called i7, and the bad ones are encapsulated into a low frequency, called i3.
So, what if something goes wrong (or is it too low to tolerate)? Then block this part of the core, and another part of the core can be used to do CPU (quad core, dual core).
But! There is a turning point!
High-end low-end market there is a proportion of! For example, when you sell one piece of i7, you sell 10 pieces of i3. But if the rate of good quality is higher, the quality is too high. But we have to have a sales strategy to high end of the market, so some originally qualified i7 film will be forced to become reduced frequency of I3 film.
Overall, that's why i7 is selling more expensive than i3. Yes, the cost of production is the same, because the root is produced together! But quality is different.
Sometimes, even if the core quality is good, it will still have to be cut down or shielded, which is a purely commercial strategy.
And now, Intel limits overclocking, but AMD does not limit, so when this happens, the user will force overclocking to the high frequency. That's why you often see "super high because of good quality".
Some impressive examples, such as the AMD's three core processor, were four cores with a bad screen. But these are bought the core is really good, there are not so many bad core, and cannot hit the three core, this cost-effective brand. The vendor shields some of the core of some of the better Quad cores into three cores. Thus, the so-called folk "open nuclear", that is, shielding off the fourth core open. There are more impressive examples of open two cores into four cores... Of course, this sort of thing depends on the lot and luck.