03-29-2006, 02:31 PM

Okay I'm looking into buying the macbook pro and it says its Intel Duo 2.16 Ghz, now does this mean it has two processors delivering in total 2.16 ghz of processing power... or is it 2x 2.16 ghz processors delivering 4.32 ghz of processing power??

03-29-2006, 02:44 PM

I believe it means one processor, two cores, delivering 2.16Ghz.

03-29-2006, 02:51 PM

The Core Duo is like the AMD X2. 2 cores each going 2.16Ghz.

03-29-2006, 02:57 PM

So total for the processing speed would be 4.32Ghz ?

It seems they would tout that a little...

03-29-2006, 03:06 PM

But dual processing systems don't give the equivalent of a 4.32GHz system really.

Any such speed measurement is crude.

Vicky

03-29-2006, 03:28 PM

A short answer: No, a Dual core 2.16GHz machine isn't the equivalent of a 4.32GHz machine. I'll try to explain the difference between Dual Core vs. Dual Processor first cuz that's somewhat important, and then hopefully sum up w/ my reasoning as to why 2.16GHz Dual Core isn't the same thing as 4.32GHz.

The way I like to describe the Dual Core vs. Dual Processor is as such... (Please pay SPECIAL NOTE to the use of 'Dual Core' vs. 'Dual Processor')

In a Dual Processor machine, you have two actual CPU chips, each with their own core, and likewise, each w/ their own mounting socket. Each of these CPUs has their own designated system Bus channel through which instructions can be passed to the actual CPU to be processed. Now since each CPU is it's own, there is no system cache to share.

In a Dual Core machine, you actually only have one CPU. This CPU has two individual cores within it, and because it is only one CPU, there is only one sytem Bus channel. Now how the CPU is designed determines how the cache is handled, but regardless, there is only one cache to be used by both cores. The MBPs have a 'smart cache' system where the 2MB L2 cache can be dynamically split depending on the load each core has, or the size of the instructions it is handling. Theoretically a Dual Core machine can still handle what a Dual Processor machine can, yet it has to share one cache, and only has one system bus to pass data in.

In end, the two are essentially the same, except the Dual Core machine has two bottlenecks when compared to a Dual Processor machine: the bus channel and the cache.

In a Dual Processor machine, you should be able to handle exactly twice the load, but there are always other things that will determine whether or not this will actually happen (RAM, Motherboard, etc.). Theoretically, a Dual Core machine should be able to come close to handling twice that of a Single Core machine, but you're going to run into a few extra bottlenecks that you wouldn't encounter in a Dual Processor machine.

So in the end, no you don't have the processing power of a 4.32GHz machine... Personally, I wouldn't even equate a 4.32GHz machine to being twice as fast as a 2.16GHz machine, or anywhere near it for that matter. That would be like comparing a 900MHz machine to a 1.8GHz machine. There are a LOT of other things that come into play, specifically Bus speed, RAM speed, etc. Rather, you'd be somewhat closer to having two machines, each one running at 2.16GHz.

Hopefully this helps, and hopefully I haven't forgotten or mis-stated anything...

03-29-2006, 03:39 PM

Excellen stuff Slyydrr—just one thing. The impact of a dual processing system's speed will be limited by how much the application in use is optimised to use a dual processing system (be that a dual processor or dual core system).

Vicky

03-29-2006, 04:33 PM

That's a very good point to make Vicky... Applications need to be optimized for hardware upgrades, whether it be a Dual Core system, Dual Processor system, or even a simple Multi-Threaded system. That's why often times when people are doing RAM tests on a Multi-Threaded or Dual Core system, or CPU stressing in general, they tell you to run two instances of the program simply because they programs themselves aren't written to use both cores/threads/CPUs, and therefore only use up 50% of the maximum CPU power available.