question about GHZ

Grumpysally

This may be a daft question but I can't find the answer on any tech sites ( or if the answer is there I'm not techie enough to recognise it ):eek:

If a processor is dual core or quad core etc. does the speed refer to each of the cores, eg dual core with 1.7GHZ speed doubles up to 3.4GHZ in that computer?

I'm trying to choose a new laptop for DD2 and understand everything else I am comparing except for the processors.

The laptop I am currently using has 'Intel (R) core (TM) i3-2370M CPU @ 2' (I assume the @2 means dual core.)

In fact now I think about it, are any computers actually manufactured with a single core processor these days?

Thank you

InsideInsurance

Each core is identical and the speed quoted is the speed that each core runs at.

It would be disingenuous to add them up, though that hasnt stopped budget hifi systems for decades, as by simply having double the number of cores doesnt result in things automatically being twice as quick

Kernel_Sanders

Not a daft question at all. I don't know if two cores can work on the same process at the same time, and I doubt if most people on this board know either.

kwikbreaks

Depends what you mean by "same time" if you make the time window wide enough - say a couple of seconds - a core can work on many processes if you make it small enough it's only a single instruction from a single process.

For best performance on multicore processors the program needs to run multiple threads then at any given instant it may have as many threads active as there are cores.

All operating system tend to run a lot of processes in parallel anyway though so multiple cores will bring a performance gain over single. That's why they build them. There is a smallish overhead for the operating system handling the scheduling though.

poppellerant

The speed refers to the overall speed of the processor. So if you bought a 2.4GHz processor, all the cores would run at a maximum speed of 2.4GHz when needed.

Kernel_Sanders

From en.m.wikipedia.org/wiki/Multi-core_processor :

The improvement in
performance gained by
the use of a multi-
processor depends very
much on the software
algorithms used and their
implementation. In
particular, possible gains
are limited by the fraction
of the software that can
be run in parallel
simultaneously on
multiple cores; this effect
is described by Amdahl's
law.

That is what I meant by "the same time".

kwikbreaks

AlisonW wrote: »

The laptop I am currently using has 'Intel (R) core (TM) i3-2370M CPU @ 2' (I assume the @2 means dual core.)

I think its a truncated Intel Core i3-2370M @ 2.40GHz

That one does have 2 physical cores but a feature of Windows may show it having 4 (2 logical cores per physical)

Here's a link where I found those details - http://www.cpubenchmark.net/cpu.php?cpu=Intel+Core+i3-2370M+%40+2.40GHz&id=761

You can find details on just about all processors in use on that site.

Windows Task Manager shows a little graph for eash logical core usage on the performance tab. On most windows you can bring it up from CTRL-ALT-DEL key combo or right click onan empty portion of the task bar.

Although the processor is important it isn't the only factor in how well a PC wil run.

Grumpysally

Thanks for the replies folks.

Just checked my old ( prehistoric ) desk PC (which is still running XP)

That, apparently is 3.06GHZ and that runs at the speed of a snail. Which I suppose means that processor speed isn't everything.

Will go for higher GHZ machine and maybe less GB of memory to keep cost reasonable. Can always add external memory and DD will only fill it full of junk anyway.

paddyrg

http://www.pcpro.co.uk/news/359254/2-8ghz-2-8ghz-doesnt-equal-5-6ghz-says-asa

No, and you're not allowed to advertise it as such :-)

Kernel_Sanders

AlisonW wrote: »

That, apparently is 3.06GHZ and that runs at the speed of a snail. Which I suppose means that processor speed isn't everything.

That's nothing to do with that (very high) processor speed. It just needs cleaning out, if you want to continue with XP. Or put Linux on it and it will fly, and you'll still be able to do most of what you could with XP (using WINE).

JJ_Egan

Memory/ RAM more rather than less .
A 3.06 machine even single core should not crawl .

DD will only fill it full of junk anyway.
Thats why its crawling i guess .