Dual Core vs Dual Processor

One benefit is packaging, allowing (2) CPUs to reside in the same approximate package size as a single CPU core ... the natural progression of this logic is that (4) CPUs could fit in the same mobo space as today's dual CPU machines. With manufacturing economies of a dual core, such a scenario might allow a "quad CPU" G5 to be cost-comparable to older dual CPU G5s.

Besides cost and package economies, I expect there are also some performance gains with faster throughput between the paired CPUs.

Neat stuff ... can't wait!

Dual core has advantages and disadvantages over dual processor systems. Dual core processors will not be twice as fast as a single processor, and will not be as fast as two processors, but somewhere in the middle.

Where dual core processors shine is when handling large processes, since they don't have to transfer information over hardware to another processor. However, they won't have as much raw processing power as two equal processors.

Obviously, the quad is the most powerful solution.

If you search Google for something like "what is a dual core processor" you will find lots of results.

Hum ...

Garrett, I was under the impression that a dual core would be faster than 2 processor because, like you said, it doesn't have to transfer info ver hardware ...

Can any one clear this up?

The new dual-core processors share a single frontside bus. That means two cores must access components and memory through one interface, rather than having a dedicated path. If everything were equal, this would degrade performance when compared to two individual processors.

However the new 970MP cores include twice the L2 cache (1MB), and are accessing DDR2, PC2-4200 memory (4.2GB/s, 533Mhz) instead of PC3200 (3.2GB/s, 400Mhz). That should erase any performance gap.

Hi,

"Dual core processors will not be twice as fast as a single processor, and will not be as fast as two processors, but somewhere in the middle."

Why will Dual Core be slower than two processors? They ARE TWO PROCESSORS on a single chip.

These systems also have faster memory and PCI-E is faster than PCI-X so there are some other factors.

Best Wishes,

Mitch

They ARE TWO PROCESSORS on a single chip.

No, not two processors, just two cores on the same die. BTW I think Coadey is right about the increase of performance due to bigger cache and faster RAM.

I'm not sure that a Dual-core processor would always be slower than two processors, I think it would depend on the kind of task to be done, not all of them would require that much bus bandwidth and some might benefit from the fact that data being handled by the two cores simultaneously does not need to go over the bus at all until it's sent to the RAM. Of course this is all theoretical, and I am personally no specialist ...

Hi,

"No, not two processors, just two cores on the same die."

I think that is incorrect. Dual Core means dual CPU's on a single chip. This definition is consistent with the performance increases that Apple is claiming.

Check here:
http://www.google.com/search?hl=en&lr=lang_en&oi=defmore&defl=en&q=define:Dualcorechip
"Definitions of Dual core chip on the Web:

* A chip that contains two CPUs and (possibly common) caches. "

"A dual-core CPU combines two independent processors and their respective caches and cache controllers onto a single silicon chip, or integrated circuit. "

Best Wishes,

Mitch

It is very dependent on the process involved.
If you are executing two processes on the machine then a dual processor machine has the performance edge because each processor has it's own frontside bus.

If you are executing a single threaded process that has heavy activity in the cache and both processors need the data, then the dual core would probably have the advantage.

In most cases the dual processor will have the advantage because of the individual processor busses.

PCI Express only deals with the peripherals and most peripherals outside of video cards don't come anywhere needing PCI Express bandwidth.

The newer machines all have the same architecture while the last machines had two different system boards. One supported 4 Gigs vs 8 Gigs of RAM. I would stay away from the low end G5 machines that only supported 4 Gigs. If there is a sale and you can get the last generation 2.3 GHz machine for a lot less than a Dual core machine; go for price.

Kent

Here's an interesting PowerMac G5 dual core vs dual processor benchmark:

http://media.99mac.se/g5_dualcore/

Take it for what you will.

If I just make home movies and edit photos, would I be better off gettinga single dual core with more ram and disk space or the two dual core with no upgrades. Is there a huge difference between the dual vs the quad for a home user?

thanks

For the home user my vote would be the single dual core with more RAM and added storage space.

I usually like Wikipedia for the general accuracy of their definitions and more importantly, for the amount of them that are available. However, I find that their definition of processor is vague at best, and I feel left with a feeling of misunderstanding after reading the article. I felt more knowledgeable after reading what AMD and Intel had to say on the subject (their articles were more technical but also much more precise).

One thing remains : whether there are two cores or two processors, they both share the same bus (at least current ones such as the Pentium D and the PowerPC970MP - aka G5 - and maybe the all-new Dual-core Xeon - interesting that Apple launch their new G5 within days of its release, it makes me wonder if it is coincidental or not - but I think that at least the next generation Xeon will have two separate buses, one for each core) which means that when buss access is required, a Dual-core chip will have twice less bandwidth than a Dual-processor, which could result in some performance decrease. Its advantage over the Dual-processor, however, is that with the "old" design, when the two processors needed to communicate, they were forced to do so via the FSB, whereas with the new, Dual-core design, they do not need to go through the bus to exchange data.

This definition is consistent with the performance increases that Apple is claiming.

Interestingly, Apple is claiming a performance increase from their Quad G5 over the previous Dual 2.7, not an increase from the Dual-core 2.0 and 2.3 over the Dual 2.0 and 2.3 G5. I did not see any comparison between these old ones and the new Dual-cores on their website, just a comparison between the Dual 2.7 and their Quad Core 2.5, which is obviously faster. I did not look at the updated PowerMac pages very long, though, so I could have missed something.

Thanks for your comments.

I suggest getting the Quad for a longterm, most cost effective solution.

The reason is the cooling system on the dual core is setup up for four cores, even though it uses two, suggesting the dual cores will be obsolete soon.

Since all computers will be dual core standard real soon across the line, the PowerMac will of course have to be Quad across the line.

Buy a dual core now and with software and OS changes you'll be stuck like the single processor PowerMac G5 owners with nothing more than a glorified imac.

There is no evidence that Quad cores are as equal to performance as 4 processors.

I can run two 3D games at once on my dual processor, doesn't mean a dual core can do the same or a Quad can run four.

Only when tests have been done will we know if we doubled our performance or not. I suspect not, but will be pleasantly surprised if it was.

The coooling system doesn't suggeest that.
Economy of scale. Build one cooling system. It's inherently cheaper than making two and trying to support them both.

It's like the motherboard. One design is cheaper.
Previous G5 machines had two different system boards. One that supported 4 Gigs of RAM and the other 8.

It's is clear that a Quad is very close to the performance of 4 individual processors. A DP, Dual Core IS a four processor machine. Two processors share a package.