The Definitive Dual Processor (crap, Dual Core) Definition

[dpaanlka]

I see that some people who call their Macs "dual processor" or "quad processor" systems being shot down and corrected now and then. "It's COREs, not processors." But is not a "dual core" basically just two processors on the same board sharing the same cache and bus?

Doesn't that still make it technically two processors? Since when is a processor defined as having an independent, dedicated bus and L2 cache? Can I free myself and tell people the Mac Pro on my desk has four processors? I mean, it technically does, doesn't it?

"Four processors" sounds a lot more impressive (and easier to understand for many people) than "four cores."

What is everyone's take on this?

 

[mkrishnan]

My take is that we really do have too much time on our hands.

 

[dpaanlka]

My take is that we really do have too much time on our hands.

I always have plenty of time for everything.

 

[840quadra]

To me, it is pretty clear that they should be called multiple cores as opposed to multiple processors. It is also what Apple states in the system profiler, and on sales material for the system. Intel also shows similar within their documentation.

My Macbook has 1 processor with two cores. .

 

[kalisphoenix]

I see that some people who call their Macs "dual processor" or "quad processor" systems being shot down and corrected now and then. "It's COREs, not processors." But is not a "dual core" basically just two processors on the same board sharing the same cache and bus?

There are many ways a "quad core" machine could be set up (okay, three) -- 1pX4c,2pX2c,4px1c.

A "quad processor" machine could have a number of cores in any multiple of four.

So I prefer using "core" because it's somewhat more precise -- even though it crumbles because of the way those cores could be arranged in the machine's processor. We saw this when the dual-core G5's came out. "Is it a dual-processor or a single-processor/dual-core?" It's confusing.

(Not to mention that there are some architectural differences that result in performance differences...)

 

[bearbo]

i think dual core is when you have two core on one board, aka one processor, two core.

quad core is when you have 2 processors (boards), and each have 2 cores

dual processor is when you have two processors(boards) and each have one core.

if you open up a dual processor G5, you see distinctively 2 compartment of independent processors, but if you open up a dual core G5 you see one compartment

a chip is a processor, but a chip might be comprised of one OR two core, the hence dual core on one processor.

we have yet to have a quad processor mac.

 

[dpaanlka]

To me, it is pretty clear that they should be called multiple cores as opposed to multiple processors. It is also what Apple states in the system profiler, and on sales material for the system. Intel also shows similar within their documentation.

My Macbook has 1 processor with two cores. .

View attachment 65259

Possibly for the system's identification that may be true. But in Apple's CHUD Processor System Preference panel (not even third party) we see this:

a chip is a processor, but a chip might be comprised of one OR two core, the hence dual core on one processor.

I know that's what the term dual-core means. But each core really is an entire processor. That "chip" they're sitting on is, essentially, a really tiny daughtercard. Is it not?

There were lots of systems in the past that didn't have any L2 cache at all, and/or shared the processor's bus with other components, even other processors. So none of that can be used to define a single whole processor.

EDIT: Also, Activity monitor lists several panes as "CPU Usage" - so each of those is a CPU? It doesn't say "Core" usage:



Continuing, third party apps also recognize them as multiprocessors (rather than cores):

 

[mkrishnan]

Possibly for the system's identification that may be true. But in the Apple CHUD control panel (not even third party) we see this

I think it's something like asking what the definition of a kilobyte is. There is more than one right answer because there is more than one valid perspective. From a hardware design standpoint, because resource sharing and board layout are not the same for cores and separate processors, it makes perfect sense to call each discrete chip a processor, and then refer separately to how many cores it has. But from the operating system's perspective, the Mac Pro motherboard has four available CPUs to which CPU processing tasks can be independently assigned.

 

[WildCowboy]

I think it's something like asking what the definition of a kilobyte is. There is more than one right answer because there is more than one valid perspective.

No, there's only one definition of a kilobyte...the other folks are just wrong.

 

[dpaanlka]

Is it not then unfair to make a distinction of a MacBook Pro as having two "cores" but the Dual Processor Power Mac G4/G5 systems as having two "processors" - because those are cores too!

And what about the dual processor Power Macintosh 9x00 systems. Those shared both the L2 cache and bus, just like the dual "core" systems do today... it had two processors mounted to that big daughter-card, and L2 cache was located externally on the motherboard. Why would they call that dual processors and today's chips dual core?

 

[bearbo]

my point is (apology for underestimate you ) there needs to be a way of distinguish 2 CPU on one board sharing this and that, and 2 CPU on 2 boards, not sharing anything..

and since the former is proven more sufficient, you need another name for that...

 

[dpaanlka]

my point is (apology for underestimate you ) there needs to be a way of distinguish 2 CPU on one board sharing this and that, and 2 CPU on 2 boards, not sharing anything..

and since the former is proven more sufficient, you need another name for that...

See above post about the "dual processor" Power Macintosh 9500 and 9600.

EDIT: Or was that a response to that post? I'm not sure I understand what you mean...

 

[840quadra]

Is it not then unfair to make a distinction of a MacBook Pro as having two "cores" but the Dual Processor Power Mac G4/G5 systems as having two "processors" - because those are cores too!

And what about the dual processor Power Macintosh 9x00 systems. Those shared both the L2 cache and bus, just like the dual "core" systems do today... it had two processors mounted to that big daughter-card, and L2 cache was located externally on the motherboard. Why would they call that dual processors and today's chips dual core?

I am familiar with CHUD, and also am familiar that it is intended to be used as a diagnostic tool for programmers. I also understand that Multithreaded programs will see them as unique and independent processors.

I guess a decision has to be made wether the marketing, or the software is correct with defining what term is correct.

I am leaning on the marketing side myself.

 

[bearbo]

See above post about the "dual processor" Power Macintosh 9500 and 9600.

EDIT: Or was that a response to that post? I'm not sure I understand what you mean...

i'm not too familiar about 9500 and 9600, but i'm assuming the 2 CPUs are not on the same circuit board?

 

[dpaanlka]

I am leaning on the marketing side myself.

But as we can see, the marketing changes over time. We had the "dual processor" Power Macintosh 9600 with what is essentially the same exact thing as today's "Dual Core" chips - I think it is just that... Marketing.

Software, however, has never changed it's opinion of how many processors one has. I have to lean towards software, since I would also imagine it (and it's writers) know my machine better than marketing people.

i'm not too familiar about 9500 and 9600, but i'm assuming the 2 CPUs are not on the same circuit board?

No, they are on the same physical board, and they share the same bus and L2 cache - just like today's "dual core" chips - but they were called dual processor!



Also, calling the Mac mini "dual core" but the Power Mac G4 "dual processor" leaves the impression that the G4 is somehow not dual core.

 

[mkrishnan]

No, there's only one definition of a kilobyte...the other folks are just wrong.

That's what they told me about you!

 

[bearbo]

No, they are on the same physical board, and they share the same bus and L2 cache - just like today's "dual core" chips - but they were called dual processor!



Also, calling the Mac mini "dual core" but the Power Mac G4 "dual processor" leaves the impression that the G4 is somehow not dual core.

but are those two CPU on one chip?

in the case of mac pro, everything is on the same motherboard, but they still are on their own 2 separate chips... aka can you physically separate the 2 CPU on the 9500/9600?

 

[dpaanlka]

in the case of mac pro, everything is on the same motherboard, but they still are on their own 2 separate chips... aka can you physically separate the 2 CPU on the 9500/9600?

No, you cannot.

 

[bearbo]

No, you cannot.

oh. then i'm not sure why can that not be called dual core

 

[bearbo]

oh. then i'm not sure why can that not be called dual core

but aside from that... the systems today can still distinguish between DC and DP, eh? i mean, it's relatively consistent

 

[dpaanlka]

oh. then i'm not sure why can that not be called dual core

Or, why that can be called dual processor, but a Mac mini is dual core?

but aside from that... the systems today can still distinguish between DC and DP, eh? i mean, it's relatively consistent

Didn't you see those screenshots of mine? Its totally inconsistent! Actually, there are far more references to "processors" than "cores."

 

[840quadra]

But as we can see, the marketing changes over time. We had the "dual processor" Power Macintosh 9600 with what is essentially the same exact thing as today's "Dual Core" chips - I think it is just that... Marketing.

Software, however, has never changed it's opinion of how many processors one has. I have to lean towards software, since I would also imagine it (and it's writers) know my machine better than marketing people.

You make a good point, however you are asking for a definition that you can use to tell others. Since marketing is paying money for ads, documentation, and others, it would make sense to use the marketing name for it.

Is it a Powermac G5 Dual 2.0, or is it a Dual 2.0 970fx Macintosh? Both are correct, but one is also easier to understand and discuss for more of the population than the other, mostly due to marketing.

 

[iMeowbot]

No, they are on the same physical board, and they share the same bus and L2 cache - just like today's "dual core" chips - but they were called dual processor!

I think you're getting to the part where this all bogs down, it's this idea that a CPU is "a chip". I doubt that this argument would even have come up in the past, when a CPU took up a few boards or a boxful of 'em.

 

[bearbo]

Didn't you see those screenshots of mine? Its totally inconsistent! Actually, there are far more references to "processors" than "cores."

when we are only talking about apple's own callings, apple didn't call all the CPU processors, they only called them CPU... like 4 CPUs in activity monitor and so on.

and the whole "if 2 CPU on the same chip, it's called dual core, if 2 CPU on different chip, it's called dual processor" is still consistent

it's another story with 3rd party calling, they are never consistent

 

[dpaanlka]

Is it a Powermac G5 Dual 2.0, or is it a Dual 2.0 970fx Macintosh? Both are correct, but one is also easier to understand and discuss for more of the population than the other, mostly due to marketing.

I agree that multiple definitions are correct. But I disagree with your "understanding" opinioin. If i tell my friends "well this is a dual processor, four core system" they have no idea what the heck I'm talking about, and it takes further explaining and just overall sounds much less simple (and much less impressive) to say "this has four processors" - which it does.

Basically, we (together) need to right now come up with a concrete definition of what the difference between dual-core and dual-processor actually is, and for that matter if there even is one.

I call for the recognition that "processor" and "core" are interchangeable, should be accepted as such in discussion, and people who say Mac minis are dual processor and Mac Pros are quad processor should not be "corrected" because they are, after all, correct.

when we are only talking about apple's own callings, apple didn't call all the CPU processors, they only called them CPU... like 4 CPUs in activity monitor and so on.

False. That control panel that says "Processors: 4" is an Apple control panel. It's part of CHUD, which is part of Xcode.

and the whole "if 2 CPU on the same chip, it's called dual core, if 2 CPU on different chip, it's called dual processor" is still consistent

But that definition is no good either because it's implying that each core is not an actual processor, which they are.

it's another story with 3rd party calling, they are never consistent

They all seem pretty consistent - they all seem to call them processors.