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Author Topic: How will faster computer processors be made in future?  (Read 3889 times)

Lor Gynoid

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Lor Gynoid  asked the Naked Scientists:

Hi Chris

How are they going to continue to make computers faster, as the
media claims will continue to happen?

(I'm not counting putting more processors on the same chip,
here.)
 
Lor Gynoid, in Second Life

What do you think?


 

Offline LeeE

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How will faster computer processors be made in future?
« Reply #1 on: 23/06/2008 18:20:02 »
Without going down the parallelisation path, you can make computers faster by increasing their clock speed i.e. simply making them run at higher speeds, or by designing them to do more work at the same clock speed.

In general, reducing the size of the switches on the chip reduces their energy requirements and allows them to operate faster.

Designing CPUs to do more work at the same speed is a little more complex but generally comes down to performing multiple operations at the same time.  This sounds similar to parallel processing but instead of performing the same operation many times in parallel, multiple different operations are performed in series in what is known as a pipe-line.  For example, if you need to do an Add followed by a Multiply, the first stage of the pipeline would be the Add operation and the second would be the Multiply (ignoring fetches etc.)  This means that once the Add op has been completed and passed onto the second Mult stage, the first Add stage can start on another Add op for new data.  A good analogy for this is an assembly line where raw materials, or sub-components, go in at one end of the assembly line and the finished product comes out at the other end, after passing through each stage of the assembly process.

Pipelines, however, introduce latency.  This is the delay between putting something in at the start and getting something out at the end, and in general, the longer the pipeline, the greater the latency.  Pipelines, just as with assembly lines, only hit their maximum production rate once every stage of the pipeline is working i.e. once it is full, but unlike assmebly lines, computers have to frequently change what they're producing, which can mean flushing, or clearing out, the pipeline before restarting it again.

Another way in which the design can be made to do more work in the same amount of time is by using techniques like predictive branching and speculative processing.  With these techniques, algorithms are used to predict the outcome of an earlier stage in the pipeline and perform the next or subsequent stages of processing before the answer is known - if the prediction is correct then the answer has been obtained more quickly but if it turns out to be incorrect the answer must be discarded and then recalculated.

In the longer term, we are likely to see the semi-conductor switches replaced by optical switches, which can function at even higher clock-rates, but this is still some way off.
« Last Edit: 23/06/2008 18:24:10 by LeeE »
 

Offline peppercorn

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How will faster computer processors be made in future?
« Reply #2 on: 25/06/2008 19:07:37 »
Longer term we are also promised Quantum computers as a practical means of everyday computation...

http://en.wikipedia.org/wiki/Quantum_Computation

... there's a few hurdles to overcome first though!
 

Offline Alan McDougall

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How will faster computer processors be made in future?
« Reply #3 on: 29/06/2008 10:42:36 »
The quantum computer will advance computing speed unimaginably. I have read that a quantum computer might be able to calculate in a minute what the fastest computer on earth, such as the CRAY could do in a thousand years.

This is of course till in the speculative realm.

Alan
« Last Edit: 29/06/2008 10:46:14 by Alan McDougall »
 

Offline graham.d

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How will faster computer processors be made in future?
« Reply #4 on: 29/06/2008 19:25:33 »
I think the trend of improvement with small steps to existing technologies will continue for a while yet. Raw computing speed related to the clock speed and how fast the logic gates will switch will get faster and, as ably explained by Lee, techniques will continue to be employed to pipeline the instruction sequences. The use of multiple processors on a single substrate is also a trend, especially in specialised applications that can make use of parallel processes; this is particularly true of the games industry, but general purpose compiler design that can make good use of this can be hard. The increasing speed and transistor density of semiconductors is not without problems that need to be solved. With feature sizes now (for production leading edge designs) below 45nm and over 500 million transistors on a chip, one of the biggest problems is simply how to get the heat away quickly enough. This has not wholly been solved yet, although there are ideas on the horizon - use of carbon nanotubes is an example.

It would not be difficult to make a very fast processor but its use would be very specialised. The issue is that it is not just the speed that is trending up but also the computing power and the associated amount of memory required. For raw speed the memory needs to be on the same chip as the processor. The size of memory required makes this impractical except for the addition of smaller cache memories to allow, for example, the pipeline operations that Lee was referring to.
 

Offline Alan McDougall

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How will faster computer processors be made in future?
« Reply #5 on: 30/06/2008 08:25:34 »
Grayham,

Yes "HEAT" is and remains the barrier with present technology. The far off quantum computer will not have to deal with this problem . Regretfully I will not be around to see thereal dawn of this amazing computer At present the best they have got out of a prototype quantum compute is to factorise 15,

Alan
 

Offline Alan McDougall

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How will faster computer processors be made in future?
« Reply #6 on: 05/07/2008 08:11:30 »
The fundamental difference between quantum computing and classical computing is that while a classical computer bit has a value 0 or 1 at any given time, quantum bits or 'qubits' can exist in a 'superposition' of 0 and 1 at the same time.

Physicists believe this gives quantum computers potential processing speed far exceeding the maximum possible in classical computing.

Quantum computing has become a key challenge for Australia, with the Australian Research Council in 2000 funding the establishment of a joint national Centre for Quantum Computer Technology, with facilities in NSW, Victoria and Queensland
 

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How will faster computer processors be made in future?
« Reply #6 on: 05/07/2008 08:11:30 »

 

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