the more complex computers become, the more transistors are needed in each chip and the tigher they have to be packed. That's also mostly a manufacturing issue.
Anttech - searching for "what is a" is meaningless
The finite propagation velocity of electrical signals is one of the limiting factors, yes.echoSwe said:So what you are saying is that the length the electricity has to travel is the limiting factor?
That's generally the plan.Then why don't they just reach the max?
If you make a processor out of large transistors, small defects in the raw silicon won't make much difference. If you make the processor out of small transistors, those defects become very important. The smaller the transistors, the more perfect your raw materials and process must be. Right now, Intel is selling processors made with 90 nanometer transistor channels. The -vast majority- of the finished units cannot operate at, say, 3 GHz. Some can only run at 2 GHz, for example, and are sold as such.How come that more quality is needed to gain clockspeed?
You can make a fast computer by just trying to make one huge processor run at enormous speeds. You can also make a fast computer by connecting lots of modest processors together and letting them share the computational tasks. The vast majority of supercomputers in the world work this way -- they expoit parallel or distributed processing.What's this about the 16x200 MHz chipset that are included in one physical processor? Wouldn't that be much slower then what you are saying - that a cycle is 1/3 000 000 000 s, but 200 000 000^-1 instead?
The heat has to get out of the chip first for it to be taken away by a cooling system. The chip's packaging -- the black plastic or ceramic case you see when you look at a chip -- has a lot to do with its heat dissipation characteristics. The problem is not as simple as just "make better cooling."In theory - wouldn't AMD and Intel be able to add more transistors and just attach better cooling?
No, as has been said, the chip manufacturers use these methods to make faster processors:So, when you overclock - then you're actually making the CPU go faster. This by changing the bus speed and multiplayer - is this the same as the company itself does - change the bus speed?
Basically.What is a transistor? A switch being either 1/0, or what?
But is it THE limiting factor?The finite propagation velocity of electrical signals is one of the limiting factors, yes.
Sorry, shouldn't have asked this quiestion since it's exactly that question the whole discussion is about.That's generally the plan.
If you make a processor out of large transistors, small defects in the raw silicon won't make much difference. If you make the processor out of small transistors, those defects become very important. The smaller the transistors, the more perfect your raw materials and process must be. Right now, Intel is selling processors made with 90 nanometer transistor channels. The -vast majority- of the finished units cannot operate at, say, 3 GHz. Some can only run at 2 GHz, for example, and are sold as such.
You can make a fast computer by just trying to make one huge processor run at enormous speeds. You can also make a fast computer by connecting lots of modest processors together and letting them share the computational tasks. The vast majority of supercomputers in the world work this way -- they expoit parallel or distributed processing.
The heat has to get out of the chip first for it to be taken away by a cooling system. The chip's packaging -- the black plastic or ceramic case you see when you look at a chip -- has a lot to do with its heat dissipation characteristics. The problem is not as simple as just "make better cooling."
No, as has been said, the chip manufacturers use these methods to make faster processors:
1) They use newer fabrication technologies, enabling smaller transistors and smaller interconnecting wires.
2) They use newer packaging technologies to remove heat better from the chip.
3) They design better architectures to more intelligently schedule and execute instructions.
4) They exploit parallel processing, allowing a chip (or chips) to do the same operation to multiple pieces of data at the same time.
Basically.
- Warren
Parasitic capacitance: At high frequencies the internal capacitances of the transistor shorts, causing the tranistor to cutoff (aka stop working)
Transitor Dimensions: When you strink the size of the transitor the delays decrease but then you run into problems with electrons tunnelling through the polysilicon gate into the body of the tranistor and vice versa.
dduardo said:Look at this picture of a Field Effect Transistor:
http://www.pha.jhu.edu/~qiuym/qhe/MOSFET.gif
You'll notice that there is an aluminum sheet that is positively charged at the gate. Below it is a insulating material made of silcon oxide. And below the insulator there is a N+ region that is negatively charged. This is the formula for a capacitor. At high frequencies these capacitors are short, which basically connects the drain to the gate and the gate to the source. Your transitor is now a wire.
In the midband frequency range there is a tunnel of electrons created below the insulator. The electrons are able to pass from the source to the drain. By controling the voltage on the gate you control the rate at which the electrons pass from the source to the drain.
echoSwe said:But is it THE limiting factor?
1) But isn't the limit reached now, when they can't make the transistors any smaller? Because if they do it leads to, what dduardo said, electrons tunneling through the polysilicon gate into the body of the tranistor? Btw - what is the gate in a transistor? Is it where the electric signal exits the transistor?
Interessting. So there is a limit to how small you can make the walls of the transistor? Has this got anything to do with quantum mechanics?
It might be for some designs, but not for others. There are a variety of limitations, and any of them can be the dominant limiting factor for any given design.echoSwe said:But is it THE limiting factor?
Processors are built on silicon wafers, slices of pure crystalline silicon, which naturally have some amount of impurities scattered throughout them. A large transistor, which uses a large area of the wafer, would not be much affected by a very small spot of impurity. A very small transistor, however, could be totally ruined by it.How come? More detailed?
Of course you can make a very large, very high clock frequency monolithic processor -- that's the approach Intel's been taking for decades. An alternative approach is to build distributed computers, with lots of independent processors working in parallel. This is the approach of companies like Sun, IBM, and SGI.No you can't. You can't just make a big CPU... Explain yourself.
No. Your personal computer is probably based on a single monolithic processor by Intel or AMD.Are you saying my own computer works like this?
What I meant is this: even if you have amazing cooling systems that can remove heat at a ridiculous rate from the surface of a chip's package, that cooling system is worthless if the heat from the die itself can't make it out of the package efficiently enough.Then please correct me.
Process geometries continue to shrink. The limit has not been reached yet, but it is looming in the near future.1) But isn't the limit reached now, when they can't make the transistors any smaller? Because if they do it leads to, what dduardo said, electrons tunneling through the polysilicon gate into the body of the tranistor?
As has been explained already, the gate of a field-effect transistor is the electrode which is used to selectively deplete the transistor's channel, changing its conductivity.Btw - what is the gate in a transistor? Is it where the electric signal exits the transistor?
Get a college textbook on microarchitecture.3) Do you have any tips on where to find more information about this?
Distributed computing is already the norm in scientific and numerical computation. It does not benefit the desktop user much, because desktop tasks do not lend well to parallelization.4) And this is what will come?
You're asking questions that really require several years of education to "wholly" answer, so you're going to have to deal with some basic answers.What's the difference between semi conductors and transistors? The whole, not the "basically" difference?
Because the impedance of a capacitor is frequency dependent. The displacement current is proportional to the rate of change of the electric field. The faster the field changes, the more displacement current you see, and the lower impedance the capacitor appears to have.Why does this happen?
There isn't a specific hard limit like a brick wall. Instead, the limit is a fuzzy area where it becomes increasingly difficult (and decreasingly economical) to make smaller structures. It does indeed have to do with quantum mechanics. Electrons have characteristic wavefunctions which are not localized. If the size of your barriers is comparable to the size of the wavefunction of the electron, the electon can spontaneously appear on the other side of supposedly impenetrable barriers. You essentially cannot trap electrons in very small spaces. Much research is being done on the behavior of electrons in "low-dimensional" spaces, like quantum dots.Interessting. So there is a limit to how small you can make the walls of the transistor? Has this got anything to do with quantum mechanics?
Try not to think of a processor's speed in terms of its master clock cycle; that's very deceptive. Novel processor architectures, compiler architectures, heat rejection systems, packaging, and more all contribute to the computational power of a computer.I've heard some approximations about when the limit for our technology will be reached, and they were 4, 5 and 10 GHz.
That's one approach, but it's not very practical. There are better ways to build faster computers, as we've already explained.Now, I know this is approximations, so don't comment on these numbers, because they just give you a feel for it (...). What more can be done to increase the clock speed now? Since raised voltage can increase the frequency, will they do that, and start shipping the CPUs with water cooling, and in the end liquid nitrogen or something like this?
Electrons do not freeze. On the grand scheme of things, liquid nitrogen is really not very cold.(And if they ship it with liquid nitrogen - doesn't the electrons freeze/the current stop?)
The same limitations we've been discussing all along.What makes could make the development come to a stop, at these frequences?
Yes, spintronics is a new and very promising technology that uses the spin states of electrons to encode information.If you consider the spin of electrons - can you do anything from that?
Your responses in this thread indicate that you don't understand that.echoSwe said:hey graphic7, don't you think I understand that? What do you take me for, Honestly??
What's alpha?
chroot said:Transistor "switching speed" is mainly limited by gate capacitance, which in turn depends mostly upon size. Smaller transistors switch faster.
As it happens, transistor speed is less a limit of processor speed as is the speed of electrical signals propagating across the chip.
- Warren
Wikipedia tends to be a good resource for distillations of technical items. Here is the Wikipedia page for the DEC Alpha:echoSwe said:Found this on alpha
http://www.lrz-muenchen.de/services/schulung/unterlagen/Meier-Fritsch/sld007.htm
A processor is limited in its frequency because of physical limitations and practical considerations. The faster a processor runs, the more heat it generates. This heat needs to be dissipated, otherwise the processor can overheat and malfunction. There is also a limit to how much power a processor can safely consume, which can also be exceeded at higher frequencies. Additionally, as the frequency increases, the amount of time the processor has to complete each instruction decreases, making it more prone to errors.
A processor's frequency is determined by its clock speed. This is the rate at which the processor's clock circuitry switches between high and low voltage states. The faster the clock speed, the higher the frequency of the processor. However, other factors such as the microarchitecture, instruction set, and manufacturing process can also affect a processor's frequency.
Yes, a processor's frequency can be increased through overclocking. This involves manually adjusting the clock speed to run the processor at a higher frequency than its designated speed. However, this can also lead to stability issues and reduce the lifespan of the processor. Manufacturers often limit the maximum frequency of their processors to ensure reliability and longevity.
Running a processor at a higher frequency can result in increased performance, as it can complete more instructions in a given amount of time. However, it also leads to higher power consumption and heat generation. This can impact the lifespan of the processor and may require additional cooling measures to prevent overheating.
No, a higher frequency does not always equate to better performance for a processor. While it may be able to complete more instructions in a given amount of time, other factors such as the number of cores, cache size, and microarchitecture also play a significant role in overall performance. It is important to consider all of these factors when evaluating the performance of a processor, rather than just its frequency.