# Tag Info

1

No, it would be normal to clock the CPU at 50MHz. Or double the input clock to 100MHz for example, if the design is fast enough. Now you know the memory stage takes 5 clock cycles, so you stall the CPU when it can do nothing because it is waiting for memory. Then there is a obvious gain from compiling your code to minimise memory accesses and their ...

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1) Any time there is current flow, heat is generated by the collisions of the electrons. 2) Yes, generally, the correlation is linear. 3) It is very unlikely that CPU manufactures optimize the position of individual transistors, to minimize the heat generated (they are all inside the same casing). When a CPU is "idle", although it uses a minimum amount of ...

19

All current flow in anything that isn't a superconductor generates heat. In chips, it's mostly flowing in aluminium "metal" layers (why not copper? Nasty chemical interaction with other parts of the silicon, it turns out). What causes current to flow? Every time a transistor changes state, this can be modeled as a capacitor (the FET gate of the driven logic ...

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A transistor (FET, in modern ICs) never switches instantly from full OFF to full ON. There is a period while it's turning on or off where the FET acts like a resistor (even when fully ON it still has a resistance). As you know, passing a current through a resistor generates heat ($P=I^2R$ or $P=\frac{V^2}{R}$). The more the transistors switch the more ...

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There is throughput and latency. On very simple, slow cores, the cache runs at the same speed as the CPU and can provide data in 1 cycle, so data is available immediately without stalling. When there is a cache miss, data is taken from main memory, and initial latency can be over 10 cycles. The good thing is that once the first data is available, the ...

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Yes. By using more efficient RAM, such as memory that supports burst mode. By using cache, which is faster RAM, along with a memory controller that continues to read from RAM while the CPU is busy executing what's in the cache.

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measuring time differences of radio wave reception This is related to interferometry, isn't it? That tends to be done not so much by measuring the arrival time of signals against a fast stopwatch of some sort, but by measuring phase differences. If you have a 1GHz signal and can measure its phase to within 1%, that's actually more useful than a 10GHz ...

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I'm don't know about high frequencies, but there's a neat set of slides on LeapSecond.com that goes on a Powers of Ten-style journey through various levels of accuracy in timekeeping standards. Here's the list with the accuracy for each item in seconds. Perhaps others can edit this answer to fill in other electronic devices. $10^{-1}$ (10%): Human heart ...

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I've been curious for awhile now ... and was wondering if there exists components that provide clocks much faster than a typical CPU can, such as up to 10 GHz or higher. Opto-electronic Oscillators (OEOs) are oscillators that take a photonic signal, like a pump laser, modulate it, and convert it to an electrical signal using a photodiode. The signals ...

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there exists components that provide clocks much faster than a typical CPU can, such as up to 10 GHz or higher. As mentioned in other answers, it's currently possible to get semiconductor VCOs with output frequency into the 20-30 GHz range. For stability, these oscillators typically need to be used in a phase locked loop (PLL) referenced to a high ...

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You can buy commercial oscillators that run up to 6+ Ghz without too much trouble. Higher frequency oscillators can be made, but they generally have to be designed for a specific use, because just the device packaging starts to become problematic at very high frequencies. In general, these sorts of oscillators aren't that precise, at least by themselves. ...

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The required clock speed/efficiency (calculations per second) of your processor is based on the complexity and efficiency of your program. A simple but poorly programmed application could need a super computer compared to how another programmer can do it! The complexity, and things that need to be done are the main factor to dictate how fast it needs to be. ...

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