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


I’ve read that AMD’s 2.0 GHz processors are comparable to Intel’s 3.0 GHz
processors. That seems totally counter intuitive. Why would that be?

To be totally honest, this is one of those areas that I actually spend very
little time on. There are hardware geeks out there that will happy rant and
rave at how one is better than the other. In fact, I kinda hope some of them
will enlighten us with a comment on this article.

But clearly, all Gigahertz are not created equal.

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In general, as your question alludes to, there’s much more than gigahertz
playing a factor in how fast your computer operates. It is a combination of the
processor’s internal architecture, the efficiency of its interfaces to the
motherboard, the composition of the motherboard itself and other items that all
combine to make systems faster, or slower, when compared to others. On top of
that, add the efficiency of many peripheral devices like your video adapter
which can also have a dramatic effect on the speed, or the perceived speed, of
your computer.

I couldn’t tell you the equation, but I know it’s complex. :-)

What I can tell you is that I don’t think it’s worth spending a lot of
energy on, unless it’s a matter of curiosity or you really have a need to
squeeze every last bit of performance out of your machine.

“… there’s much more than gigahertz playing a factor
in how fast your computer operates.”

Personally, I look at the applications and load that the server will be
handling. If you expect to get “close” to stressing the slower of the two
processors, in my mind, you’re too close for the other one as well. A 20%
difference, for example, in throughput between two processors is not make or
break to me. What is is cost, and other factors that add up to, say,
100% or greater differences. So when selecting a server, which I have done in
recent years, 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

But that’s just me.

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10 comments on “Why are one manufacturer's processors faster than another – even at the same GHz?”

  1. 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 :)

  2. 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.

  3. 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.

  4. 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.

  5. 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!

  6. 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.

  7. 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.

  8. 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

  9. The word length of the cpu affects the cpu speed. It is the amount of bits the cpu can process on an instance. (example 32bits and 64bits processors). The cpu architecture, the Cache size(2mb or more or less),and many other factors. Google for it :)


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