Comments for Why are one manufacturer's processors faster than another - even at the same GHz?

Comment from Josh on 2009-04-02

2009-04-02T19:10:38Z

There are several factors that affect program execution speed: first, the clock rate (ie. Ghz). This is the measure of how many occilations the processor can make in a given second. Next, the number of clock cycles per instruction. For example: given the same clock rate: a processor may take 2.0 clock cycles to execute one program instruction, and another brand might take 1.5 clock cycles. This would result in the processor taking 1.5 clock cycles being 1.3333333... times as fast as the processor that takes 2.0 clock cycles per instruction. Last, there is the fact that a program must be compiled to function on specific hardware. For example: a program might be able to execute in 10 instructions on one type of processor, but need to execute 30 instructions on a different architecture. All of this, and the fact that there are different types of instructions that take different amounts of clock cycles (ie: on most architectures, multiplication is just a lot of addition, so it takes longer to do), creates a complex mathematical calculation to figure out what processor will run faster. In fact the most important factor is not a part of the processor, per se; Processor Input/Output is the slowest operation performed by a program. Accessing RAM takes 100 times the amount of time it takes to process a comprably sized instruction. Accessing a Hard Disk takes 50 times THAT amount of time! Remarkably, even up to 80% of a program's execution time may be spent on memory access and other I/O!

To illustrate: given two computers running the same number of instructions, and same I/O time, for 5 seconds, on a 2.0 Ghz machine needing 1 clock cycle per instruction and an 8.0 Ghz machine needing 4 clock cycles per instruction, respectively: which is faster?

Answer: Neither! They will execute the exact same amount of instructions!

-I am working toward my second CS degree,
level of expertise: extremely high

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Comment from browny on 2008-10-23

2008-10-23T21:10:31Z

Please tell me what i should look for before buying my new laptop. The following are the things that i would do with the laptop.

The most important thing for me about a computer is its ability to perform multi task at the same time. And also to work faster when you click to either open a page because i do a lot of internetting due to the nature of my job.

Again i like movies a lot, so a laptop that have good pictures. I travel a lot also so the computer ability to work for long on battery and other things like lan connectivity and the like.

Thank you.

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A comment on: Why are one manufacturer's processors faster than another - even at the same GHz?

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Comment from Jeff on 2006-07-28

2006-07-29T05:39:22Z

To summerize it AMD does does not have a FSB. It has what is called a deticated memory bus which is built directly into the core. This greatly increases speed. Secondly AMD chips do more processes per clock. Last of all I dont know how people got the idea that you cant have a processor exceed 5ghz. My other comuter is stable at 14ghz. I have whats called phase change cooling. The reason most people cant overclock their computer that much is because of heat. Your CPU gets hot enough to cook on. When you overclock it, it gets hotter. More energy more heat.

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A comment on: Why are one manufacturer's processors faster than another - even at the same GHz?

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Comment from Derrick on 2006-05-24

2006-05-24T14:29:57Z

I'd like to know from an expert why everybody thinks AMD processors are faster than Intel's. Does AMD really have different speeds than they say they do? Because everybody says the AMD FX-60 (2.6GHz) is faster than the Intel Pentium 4 (3.8GHz). Is it because the AMD processor has faster front bus speeds? Please tell me someone. Thank you!

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A comment on: Why are one manufacturer's processors faster than another - even at the same GHz?

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Comment from mary on 2006-04-20

2006-04-20T21:15:24Z

Well put, Robert. That is so important nowadays. I work in a dedicated hosting environment, so it matters a lot to my company, but not so much to the customer. We want to have the highest end procs, and power consumption is a large part of the decision making process. We figure that out, roll it into the cost of the machine (along with a thousand other factors) and there's the monthly price.

I think processor technology is going to get insanely interesting in the next few months.

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Comment from Robert on 2006-04-17

2006-04-17T20:06:25Z

Where you said: "I try to look at the total picture ... cost, disk capacity & speed, network bandwidth, memory usage and capacity, my expectations for video performance ... and somewhere in the middle of all that ... processor speed," you left out a critical point. These days you have to start factoring in the cost of electrical power. At the rate these costs are rising, this will soon become a significant issue.

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A comment on: Why are one manufacturer's processors faster than another - even at the same GHz?

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Comment from Chris on 2006-04-16

2006-04-16T22:32:39Z

Processor speed (measured in GHz) is only meaningful when comparing to other processors with the same architecture. For the past few generations, AMD and Intel processors have used fairly different internal mechanics to do the work. So, comparing GHz between an Intel Pentium 4 and an AMD Athlon64 is like comparing apples to oranges, they are just not directly comparable. AMD uses numbers like 4000+ to give you an idea of what the comparable Intel Processor speed would be, however Intel has recently stopped using MHz measurements entirely in their processor line, instead calling them the model 814 for example.

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A comment on: Why are one manufacturer's processors faster than another - even at the same GHz?

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Comment from Vikram on 2006-04-16

2006-04-16T09:11:08Z

We now have dual core processors, simply put, thats two processors built into the same chip(lots of expensive & complicated circuitry). So maybe the days of the race to make the fasted processor based on GHz is over, we may see increase in the number of cores :)

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Comment from Lloyd Cheaye on 2006-04-14

2006-04-15T03:36:52Z

Leo,
you are the best

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A comment on: Why are one manufacturer's processors faster than another - even at the same GHz?

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Comment from mary on 2006-04-14

2006-04-15T01:42:36Z

I've done some of my own research on this, and here's what I have come up with. Up until recently, people would gauge their processor’s speed based on the GHz measurement: A 2.8 GHz processor is faster than a 2.4GHz processor. That is still true today, but there is an understanding in the processor market that the potential to increase the number of GHz a processor can stand is about to top out. The GHz limit is unknown, somewhere around 5… but once that limit is reached, the processor will not physically be able to withstand anything higher. Processor companies are looking for other ways to increase speed. Intel has always been the top dog, and until recently, they used the GHz measurement as the model number for their chips, so we're just used to judging procs based on that number, even though it's one of many ways to measure the different components that make up the speed of the processor.

I LOVE YOU LEO!

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A comment on: Why are one manufacturer's processors faster than another - even at the same GHz?

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