Is a Dual Core actually acting like 2 processors?

"Kardon Coupé" <prefer.to.DeleteThis@readon.newsgroups> wrote in message
news:f73eq9$86i$1@aioe.org...
> Dear All,
>
> I'm having a running debate at the moment with a family member, I've just
> upgraded my pc to a intel dual core, and I was telling them it is like
> having 2 processors in one....and after explaining it is a 2.13ghz, they
> were saying, "does that mean that is the a program is using 1.99ghz of
> processor power, does another program only have 0.14ghz to play with" and
> I was saying....(and I'm thinking I'm right with this). "The machine
> thinks it has two 2.13ghz chips, thus having a combined speed of 4.26ghz"
>
> Am I right in what I'm saying? or if I'm wrong, can someone explain how it
> does work, so when the conversation next arises I can explain it, and it
> will actually make sense...

It doesn't just 'think' it has 2 processors, it genuinely does have 2
processors. It just feels like 1 because both 'cores' are in the same
physical square component.

It is not accurate to say the machine has a combined speed of 4.26GHz. This
would be great, but all you have is 2 processors running at 2.13GHz. They
cannot be combined to do 1 task (thread) at 4.26GHz! They can do 2 things at
once at 2.13Ghz, but the processors cannot be pooled into 1.
 >> Stay informed about: Is a Dual Core actually acting like 2 processors? 

> It doesn't just 'think' it has 2 processors, it genuinely does have 2
> processors. It just feels like 1 because both 'cores' are in the same
> physical square component.
>
> It is not accurate to say the machine has a combined speed of 4.26GHz.
> This would be great, but all you have is 2 processors running at 2.13GHz.
> They cannot be combined to do 1 task (thread) at 4.26GHz! They can do 2
> things at once at 2.13Ghz, but the processors cannot be pooled into 1.

And then only if the program is a multi-threaded one, which hardly any
programs seem to be. Hence its somewhat more of a marketing coup, than a
practical computing improvement. In fact I didn't even notice any
improvement when I swapped my single 2Ghz core for my dual 2Ghz core. And as
a consumer, I was expecting a near double speed improvement (after factoring
in motherboard considerations - bus bandwidths, memory limitations, etc).

Incidentally, does anyone know if Windows XP Pro genuinely runs programs on
seperate cores when you choose Task Manager > Processes > Right-click on a
process and then choose Set Affinity?

Or is this just a hypothetical, interestingly worded concept rather than a
technical reality at present?

I've several times set the affinity of a seperate high CPU consuming task to
one processor whilst setting other tasks to complete on the other. Neither
task ever seems to complete any quicker...at least not noticeable so. Makes
me wonder what all the fuss is about.
 >> Stay informed about: Is a Dual Core actually acting like 2 processors?