How Is a CPU Manufactured to be a specific speed

[misterhobbs]

How does Intel (or AMD) construct their CPU in the same product line to have different clock rates? For example, the i7 3270qm and 3920xm both have the same number of transistors and 22nm manufacturing process, but how does Intel build one to be faster and the other slower? Do they start off with the same CPU and somehow reduce the clock speed or take away certain features? Do they change current and voltage? None of the above?

I'm just curious and appreciate any replies.

[tijo]

They make all their CPUs in the same way, but there are always variations, they run some tests to determine how high they can go and what features they can support and label them accordingly. Anything not passing the test for the lowest binned CPU is usually recycled. This process is called binning.

[Qing Dao]

They burn in a tiny bit of memory on the chip that specifies the settings. They actually put very few cpu's through any tests to determine their performance. They are very good at guessing it. Also chances are that even the lowliest processor in a series, if given the settings of the highest, will function just fine. Intel and AMD determine how many of each processor to make based on demand, not the ability of the processors. When they bin, first priority goes to extreme chips, then mobile chips, then desktop chips. Also in some cases, Intel or AMD disable, or have disabled parts or features of cpu's that were non-functional in order to salvage the product.

[Peon]

To put it simply, all CPUs are manufactured as Extreme Editions (or top of the line in product lines where Extreme Editions don't exist). Some come off the assembly line with manufacturing flaws that prevent them from reaching their full potential, but the vast majority are purposely crippled by Intel/AMD to meet market demand at lower price points - after all, not everyone is willing to pay $1000 for a CPU.

[tijo]

To put it simply, all CPUs are manufactured as Extreme Editions (or top of the line in product lines where Extreme Editions don't exist). Some come off the assembly line with manufacturing flaws that prevent them from reaching their full potential, but the vast majority are purposely crippled by Intel/AMD to meet market demand at lower price points - after all, not everyone is willing to pay $1000 for a CPU.

There's that too, but each cpu will at least go through a minimal amount of testing As far as I know.

[misterhobbs]

Thanks for the replies. They helped.

[Qing Dao]

There's that too, but each cpu will at least go through a minimal amount of testing As far as I know.

Every cpu is put into a special socket that takes a few seconds and tests the processor for proper electrical connectivity, but that is it.

[maverick1989]

I JUST took a class at university that involved this stuff. Basically it is all about logic. Every chip can be overclocked. To what extent, depends on how it is manufactured. The "clock" is actually a signal based on which all computations in a CPU take place. If the clock is too slow, you lower the computation speed and your CPU appears sluggish. If the clock is too fast, you your internal signals, which depend on the clock, will not be stable before the next clock "cycle". Each clock cycle gives a certain command. As such, if your previous signal is not stable, then you are basically telling it to do too much.

Think of it like asking you to run to the grocery store and then give the car for repairs except that I am forcing you to drive the car to the mechanic quicker than it is physically possible for you to come back from the grocery store. It all goes aaaaaaaaaaarrggghhhh and crashes .

CPUs are not "manufactured" for a specific speed. They are designed for a specific speed. They can be run at a variety of speeds. The 3720QM can run at the same speeds of the 3820QM without any problems. However, then Intel won't have two brackets to make money off of.

[HopelesslyFaithful]

i wish they would hack a lot of their product line...utterly pointless...why the hell do you make a B940? Just make an i3. Even the i3 is cheap and lack luster. Why make a chip that is even worse?

[niffcreature]

The b940s are probably the seriously botched chips.

To put it simplest, cpus are NOT manufactured to be a certain speed at all. They are manufactured kind of like car parts, imprecisely. And then some crazy car guy comes in and measures all of them precisely to find the perfect parts and build a super efficient super fast car.
Funny because this actually happens with cars.

What bothers me the most is that the Extreme CPUs are NOT necessarily top of the batch, they just have unlocked multipliers, which intel could do to an i3 if they wanted to and call it an i7-3960xm.