# Tag Info

1

There are three physical limits: Heat, gate delay and the speed of electric transmission. The world record on the highest clock speed so far is (according to this link) 8709 MHz The speed of electric transmission (about the same as the speed of light) is the absolute physical limit, since no data can be transmitted faster than it's medium. At the same time ...

0

Practically, it is definiteley the thermal power which is approximately proportional to the square of the voltage: http://en.wikipedia.org/wiki/Thermal_design_power#Overview Every material has its specific heat capacity which limits the cooling efficiency. Not considering the technical issues on cooling and transmission delay, you will find the speed of ...

5

The heat issue is well covered by fuzzyhair. To summarize the transmission delays, consider this: The time needed for an electrical signal to cross the motherboard is now more than one clock cycle of a modern CPU. So making faster CPUs isn't going to accomplish much. A super-fast processor is really only beneficial in massive number-crunching processes, and ...

30

Practically, what limits CPU speed is both the heat generated and the gate delays, but usually, the heat becomes a far greater issue before the latter kicks in. Recent processors are manufactured using CMOS technology. Every time there is a clock cycle, power is dissipated. Therefore, higher processor speeds means more heat dissipation. ...

0

So one question is: Is there a physical limit to CPU speed? That depends highly on the CPU itself. Manufacturing tolerances result in the fact that the physical limit is a bit different for every chip even from the same wafer. transmission delays cause another limitation in CPU speed. However, they don't mention how fast it can get. That's ...

0

The difference between a CPU and FPGA is parallelism. FPGA's are very good at performing a number of (logically) simpler tasks at once with minimal delay. More complex logic and sequences of operations are better catered for by the CPU's ALU (Arithmetic and Logic Unit). If you are interested in a common software emulation of gate design, which is typically ...

0

Other answers have addressed the specific questions at a nuts and bolts detail level, but I think there is an opportunity here to look at it from a different angle. Processors today have many millions (billions in current generation desktop CPUs) of transistors implementing a comparably large number of gates. While only a few of those gates are actually used ...

0

As you have observed, the contents of the lookup table determine whether a certain LUT is an OR gate (0, 1, 1, 1), and AND gate (0, 0, 0, 1), an XOR (0, 1, 1, 0) etc. The lookup table itself is implemented using hardcoded gates, i.e. the result is (lut[0] AND NOT a AND NOT b) OR (lut[1] AND a AND NOT b) OR (lut[2] AND NOT a AND b) OR (lut[3] AND ...

12

Actually your first guess is not as afar off as some are claiming. A CPU is built around something called an "Arithmetic Logic Unit" (ALU) and a simplistic implementation of that is to have the logic gates implementing all basic operations wired up to the inputs in parallel. All of the possible elementary computations are thus performed in parallel, with ...

1

The CPU doesn't just have 'a number' of pre-build logic gates. A modern processor has between around 50 million to several billion transistors, corresponding to many millions of gates. The CPU already has all the resources needed to execute your C++ program. The resources provided fulfill the instruction set defined by that hardware platform, be it x86, ...

7

Pretty far off. A CPU is made up of real gates (not programmable LUTs). The key operations on data are done in a block of logic often known as an ALU (arithmetic-logic unit). Inside this block is a set of gates that can, for example, AND two operands together, bit-by-bit. There's another set of gates that can add them together, and so on. When you execute ...

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To get a little more technical and expanding upon tcrosley answer (which is good btw), there are two ways a processor can really go. Either a company will: Invest into a higher speed core for the processor or Invest into more cores of the same speed Intel has taken the higher speed core course. They have invested in having much faster processors over ...

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It's all about size. Intel has recent revenue of $48 billion and 107,000 employees. GlobalFoundires, which is a divestiture of the manufacturing arm of AMD, and manufactures chips for AMD, Qualcomm, Broadcom, and STMicroelectronic among others, has recent revenues of$4.6 billion and 13,000 employees. So it is about a tenth the size of Intel. Meanwhile, ...

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