Question about "Duo" processors versus single processor

[Xenogear900]

I just got this Dell Inspiron E1505 Laptop with an Intel Centrino DUO 2ghz processor. Does that mean it has two 2ghz processor (2+2=4ghz)? I don't understand what that means.

Is it better to have a computer with just ONE big processor? I also have a desktop with a 3.4ghz Pentium 4 processor. Which computer should be faster? They both run XP Pro, they both have 1gb of ram, they both have the same programs and do the same things.

Xenogear900@yahoo.com

[guns1inger]

It depends what they are doing as to which will be faster. If you are doing something very CPU intensive, like encoding video, and the encoder is multi-CPU aware, it should use both CPUs to 100%, and be faster than your single CPU P4. If the software is no multi-CPU aware then it will only use one CPU and be substantially slower. Try running a single CPU aware game, for example, and watch it bog down on the DUO.

If you like to do multiple things at the same time you may find that you can do so more easily on the duo simply because it is able to better utilise the two CPUs to get everything done, whereas the single CPU has to do more process swapping.

Ultimately, no, you don't get a 4gHz CPU out of a 2gHz DUO. You get certain improvements under certain circumstances.

[jagabo]

Also keep in mind that, for most tasks, each core of the Core Duo is much faster than a Pentium 4 on a clock-for-clock basis. So even with applications that don't use both cores the 2.0 GHz Core Duo won't be far behind the 3.4 GHz P4.

[handyguy]

Dual processor computers have been around for years.

According to Moore's law we should be having something like 16ghz computers by now. But we don't cause the rest of the computer parts wouldn't be able to catch up.

Try the other dual core topics, you basically have what I would consider, is two computers each doing 2 ghz, (alone, isn't very fast). But the above topics describe it fine, also see other topics on this, there are a few.

[Capmaster]

The chip manufacturers have changed their strategies in recent years. They're getting away from the "faster clock is better" more towards the "more cores is better" policy. It makes more sense because higher clocks generate more heat.

That 2GHz Duo should run rings around a single 3.4 GHz P4 We have a 1.6 GHz Duo laptop that decisively put my old 2.8 P4 HT to shame

[Bjs]

Xenogear900

(2+2=4ghz)? = no , I have seen idiots in ebay and elsewhere make this crap claim .

The p4 will leave the centrino in it's quake .

The centrino , too conserve power when running only from battery , it runs at half it's designed speed ... this help's increase the battery's run time maximum .

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guns1inger

I dont see " be faster than your single CPU P4 " ... there both duals .

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jagabo

"Core Duo is much faster than a Pentium 4 on a clock-for-clock basis"

While this maybe true , there are difference's in the "p4" class ... not just a single processor type .

Dualcores with no hyperthreading
Dualcores with .
Dualcore extreme .
And the most important issue , buss cycle in mhz ... the higher this is , the faster it will go .

Not too forget the possible bottle neck problems associated when splitting to multiple thread's , and bring it back , which intel admitted too as too why 4ghz cpu's havent arrived yet , they dont want this issue too appear ... the memmory bank's are not that efficient in design as compared to the old quad cpu motherboards ... which had seperate banks of memory for each cpu installed ... now could they do some work .

Intel(R) Pentium(R) D CPU 3.40GHz 950 Presler running at 4ghz ... my new experiment
Some have them overclocked to 5+ghz using liquid nitrogen cooler's .

So who is fast now ...

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handyguy

Dont get " dual processor's" confused with "dual core's" ... different kettle of fish here .

Moore's law wasn't acurate in the first place , because of the "human error factor" and "material characteristic changes required for increase yeilds in mhz" ... having not been acurately calculated and included into the equation . Even allowing for such variances , it would have been impossible to calculate the required assumption's necessary to allow it to be anywhere near acurate in the first place , and it would never have be acurate at any point in time ... therefore , it is null and defunct .... along time ago ... and should have been abandoned and no longer mentioned .

A possible reason behind why amd went with "real world" expectation's , and intel (soon) will abandon the reference to cpu mhz for real world expectation's .

Real world expectation's is how fast a pc can perform a given task , without reference to cpu mhz and clock cycles .

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An analagoy that is simple to understand by all user's :

Take two computers , made of different component's ... place them on a line on the top of a high building ... and push one off the edge .

Which one was faster here ?

The one that fell of course ... you saw it in "real time" action .

[JohnnyMalaria]

If the software is no multi-CPU aware then it will only use one CPU and be substantially slower.

That's not quite true.

There are many multithreaded apps out there that aren't multi-CPU aware. On a multi-CPU system, Windows will tend to distribute the different threads on different CPUs. Hence, you can get benefits even without explicit coding for multiple CPUs.

See my previous post: https://forum.videohelp.com/viewtopic.php?p=1633587#1633587

[mpiper]

Just a quick comment of Moore's law.

it is relatively accurate, but was limited by the technology and concepts of the time when he stated it. it you took the performance of the processors at that time, and just track the PERFORMANCE over time, Moore's Law applies. But, since technology and implementations have changed, the physical numbers (Mhz) do not apply. That is why a 2.13 Ghz Core2 Duo processor is faster than a 3.0 Ghz single core HT, regardless of what application you run. The processor cycle speed went down, but the data processing speed went up.
Take a look at this performance chart to see what I mean:
http://www23.tomshardware.com/cpu.html?modelx=33&model1=433&model2=462&chart=181

Mike