Dual Core Processor?

Question

I've been curious. What is a Dual Core processor. I've heard it's pretty much 2 proccesors in one. Forgive the stupidity of this wuestion, but does this mean a 1.8ghz dual core processor would run like a 3.6ghz? Once again sorry for the stupidity.

Answer 1

It's basically two "cores" in one.  It's not two entire processors, and the numbers for speed do not add up.  A 2.0 ghz dual core processor runs at 2.0 ghz.  Each core runs at that speed, but the speeds are not additive.  Having two cores simply allows the processor to split the loads of work.  It's not perfect.  Programs need to be written to take complete advantage of this.  They are NOT twice as fast as single core processors for most tasks.

There are also a LOT of other factors that go into processor speed.  Suffice to say, most dual core processors (specifically the Core 2 Duo) are so advanced in technology that they are faster at speeds like 2.0-2.2 ghz than the older single core processors were at 3.0 ghz.

Answer 2

Very succinct Vincent P.

I can only add that dual cores share the same weakness of say two entire processors. The extra processor can only help if there is some work that can be split up and shared. Typically that is never more than 70% of the time for a second processor., 60% for a 3rd processor, etc. when working on a single program. Thus dual cores is usually 170% at best and often less.

So when working on a single task that cannot be divided at all -- only one core is active (well a little OS overhead can always be shifted in the real world because that is a second task group). Thus multiple core processors or multiple processors never do single indivisible tasks any faster than a single processor of the same make and speed.

But usually modern programming can find some way of splitting complex programs into many separate tasks that can run at the same time and then share out these duties to available cores/processors. On the other hand this process of splitting is seldom done to maximum efficiency and the degree varies with how much time and effort is placed into the coding and compilation as well as the sophistication of the software tools. Also the nature of the application will effect how well it can be split up in small parallel tasks.

Still modern computers are usually running many processes and applications at once - particularly OS and driver related stuff. So on average there much more opportunity for sharing work load than on the average single application itself. Thus effective CPU pwoer tends to average out to more like the optimum of 170% for two cores.