What exactly is a Dual Core ?

Question

So, Im going to upgrade my computer with a dual core processor but just need to know something::

If a product says Intel Core 2 Duo E4700 2.60GHz (Retail 775) does that mean there is 2.60GHz on each core or does it mean 1.3GHz on each core? I'm now confused because on a forum someone said that they have 2.0GHz on each core of a Dual Core Processor. Insight please!?

Answer 1

The speed is for each core.

The dual core processors are are like 2 seperate processors on a single die (the peice of silicon the make chips on).  They may share some cache and other resources, but it is basically like you are getting 2 of the same chip.  And the specs listed are for both of those.

Answer 2

A dual core processor is a CPU with two separate cores on the same die, each with its own cache. It's the equivalent of getting two microprocessors in one.

In a single-core or traditional processor the CPU is fed strings of instructions it must order, execute, then selectively store in its cache for quick retrieval. When data outside the cache is required, it is retrieved through the system bus from random access memory (RAM) or from storage devices. Accessing these slows down performance to the maximum speed the bus, RAM or storage device will allow, which is far slower than the speed of the CPU. The situation is compounded when multi-tasking. In this case the processor must switch back and forth between two or more sets of data streams and programs. CPU resources are depleted and performance suffers.

In a dual core processor each core handles incoming data strings simultaneously to improve efficiency. Just as two heads are better than one, so are two hands. Now when one is executing the other can be accessing the system bus or executing its own code. Adding to this favorable scenario, both AMD and Intel's dual-core flagships are 64-bit.

To utilize a dual core processor, the operating system must be able to recognize multi-threading and the software must have simultaneous multi-threading technology (SMT) written into its code. SMT enables parallel multi-threading wherein the cores are served multi-threaded instructions in parallel. Without SMT the software will only recognize one core. Adobe Photoshop is an example of SMT-aware software. SMT is also used with multi-processor systems common to servers.

A dual core processor is different from a multi-processor system. In the latter there are two separate CPUs with their own resources. In the former, resources are shared and the cores reside on the same chip. A multi-processor system is faster than a system with a dual core processor, while a dual core system is faster than a single-core system, all else being equal.

An attractive value of dual core processors is that they do not require a new motherboard, but can be used in existing boards that feature the correct socket. For the average user the difference in performance will be most noticeable in multi-tasking until more software is SMT aware. Servers running multiple dual core processors will see an appreciable increase in performance.

Multi-core processors are the goal and as technology shrinks, there is more "real-estate" available on the die. In the fall of 2004 Bill Siu of Intel predicted that current accommodating motherboards would be here to stay until 4-core CPUs eventually force a changeover to incorporate a new memory controller that will be required for handling 4 or more cores.

Answer 3

what kapil said

Answer 4

While technically correct, some of the other answers get a bit too technical in my opinion...you have a very good question and I wish manufacturers would clarify this better!

From what I understand, 2.60GHz Dual-Core is basically like having two 2.60GHz processors ("cores") stuffed into one.  I'm not sure you can do a simple 1+1 additon (I don't think 2.60+2.60=5.2GHz) but it should be (or feel) faster than a single-core 2.60GHz processor.

Answer 5

Both cores run at the same speed.  They have to, otherwise there would be timing complications.  

Also, having two separate 2 Ghz CPUs is not the equivalent to a  single 2 Ghz dual core processor.  The separate CPU scheme is better & faster, but there is a greater cost involved.

Even though there are two CPU cores in one package, the data output acts as though there is only one CPU.  If this were not the case, then the multi-core CPU would require 2 or more times the number of CPU input/output pins, which is not viable.

Answer 6

A dual core processor is a CPU with two separate cores on the same die, each with its own cache. It's the equivalent of getting two microprocessors in one.