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I have a new MacBook Pro, clicking on "about this mac" I see I have a:

2.66 GHz Intel Core 2 Duo

A friend has a Mac Pro and has:

2 x 2.8 GHz Quad-Core Intel Xeon

How am I to understand this: I assume I have only one CPU and he has two. What does this allow him to do that I can't. Will his machine be faster than mine, and at what? Does "2 Duo" mean I have "2 x 2" = 4 cores? Does "2 x Quad-Core" mean he has "2 x 4" = 8 cores? What is a "core" actually in practical terms, i.e. how can we expect it to effect performance?

What is the practical difference between these two machines?

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For start, your friend has Mac Pro, not MacBook Pro. – AndrejaKo Nov 15 '10 at 21:06
thanks, I just saw a screenshot so I assume you're right, how do you know for sure? – Edward Tanguay Nov 15 '10 at 21:15
there's no laptop on the market with dual processors. Or Xeons at all for that matter. That's how he knows. – Shinrai Nov 15 '10 at 21:23
The Xeons are available only on Mac Pros. The Xeons also trounce the Core 2 Duos big time. – Sathya Nov 15 '10 at 21:24
@Shinrai @Sathya You posted the way I knew how it's a Mac Pro. – AndrejaKo Nov 15 '10 at 21:27
up vote 6 down vote accepted

In practical terms, performance is relevant only if you actually have tasks that place heavy demand on the CPU/cores. So if you do lots of work with video or graphics, the extra computing power would help. But if you browse the web, read emails, watch movies or listen to music, your machine is perfectly capable of handling that for a few years to come.

Processor power is only one axis of performance. Amount and speed of RAM (memory), amount and type of disk (hard drive or solid state) etc. also influence overall performance, but again this depends on what kind of workload you have for the machine. The more important metric would revolve around a cost/benefit analysis that takes all these variables into account and considers what kind of work the machine is meant to do. Generally-speaking, top of the line hardware is low on this cost/benefit metric, because components get cheaper all the time.

To test relative performance, you can use XBench or GeekBench but those numbers may not be all that interesting.

To address your particular questions:

  • Core 2 means the second generation of the processor family. Duo means two cores. You have one chip with two cores.
  • Yes, your friend has 8 cores, spread over 2 chips.
  • Cores increase speed of certain types of operations and keep power down, compared to having single core chips.
  • You can do everything he can, but some CPU-bound tasks (i.e. movie encoding) would be faster for him since any modern program has support for parallelizing tasks, and so he can run some tasks on 8 cores versus 2. However, this does not apply equally to everything, so this kind of performance is only noticeable on very intensive tasks.
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Your answer is more comprehensive than mine, and beat me to it as well. +1. – Sathya Nov 15 '10 at 21:27
+1 for cost/benefit! That's the main difference between those two computers. – AndrejaKo Nov 15 '10 at 21:28
@AndrejaKo - I'd say the MAIN difference between those computers is about 15 kilograms and a fair amount of volume. ;) – Shinrai Nov 15 '10 at 21:40
@Shinrai Well, if you look at the from physical side, then yes. When I wrote the comment, the physical differences between computers didn't occur to me. – AndrejaKo Nov 15 '10 at 21:42
@AndrejaKo @Shinrai I assumed the obvious differences aren't the crux of the question, but they do play into the equation if portability is an issue: the MacBook Pro is clearly the winner if that's a requirement, since nobody should be a fan of lugging around a Mac Pro and the respective monitor as they need it. – roguesys Nov 15 '10 at 21:47

Each core is actually a processor. For quite some time it has been difficult to make processors with multiple cores, so computers which needed to have high performance and do large number of tasks concurrently used multiple processors.

During this decade technology advanced so much that it's practical to have two cores on a single processor. That's basically 2-in-1 package which is often better than two separate processors. Cooling is easier and so is construction of motherboards. Plus the two cores can communicate with each-other faster than two separate processors.

Form the software side there are so called "threads". Basically each simple program can only do one thing at one time. If you want to do more than one thing, like click a button while your word processor is scanning a document, you'll need to separate program into smaller components which are called threads. Computer can quickly change which tread is being executed, so it gives impression to user that there are several things happening at one time. With computers with multiple processors, each processor can execute at least one thread (there are processors which can execute more than one at one time, but I won't go into that now). Sometimes one processor needs data from thread which is being executed by the other processor. Slowdowns can happen while one processor transfers data to the other. This multi core processors are less affected by this problem because cores are all in one processor.

Now for your specific questions. You are misinterpreting the 2 Duo part. It's (Core 2) Duo, that is Core 2 is successor to Core, as we had Pentium II as a successor to Pentium. Duo means that there are two cores on that processor. Your friend has 2 quad core Xeons. His system is a combination of multiprocessor system and multicore system. Each processor has 8 cores and system has 2 processors. They are also a bit faster than your processor when measured core for core.

That means that you can run 2 applications at the same time while he can run 8 applications at the same time. This is good in cases where some of the applications are very demanding are need a lot of processor time and their work is in separate threads. It is also good in cases where there is a single thread which is very demanding because system has extra processors which can be used to execute other threads so system appears more responsive.

There is also Xeon Core comparison. Both processors are related, but Xeon processors are meant for servers where there is need to process large amounts of data and where reliability is extremely important. They are usually of very high quality. Core processors are simpler desktop and laptop versions and they are cheaper and of lower quality. Also Xeon processors use different type of RAM which can detect errors caused by background radiation (among other things) and correct them. Further more, your friend's system can take much much more RAM than your own. I don't know exact numbers MacBook Pros at the time your processor was popular couldn't take more than 4 GiB of RAM, while your friend's computer could probably take at least 16 GiB of RAM and probably more.

As for the quality part I mentioned: Basically all processors of same generation are manufactured together. At one point of the manufacture, each processor is tested. After testing, processors are graded so that the worst processors which may be inoperable are discarded, processors with light damage have damaged parts disabled and are sold as cheap processors, fully functioning processors usually go into middle class and most expensive processors are those which gave best results at testing. I expect that testing if far more strict for Xeons.

So basically, almost everything your computer can do can be done by your friend's computer but much much more faster.

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... and you beat me too. – Sathya Nov 15 '10 at 21:28

Will his machine be faster than mine, and at what?

His machine will be faster in pretty much everything. The Mac Pro has two separate Xeons running at 2.8 GHz. Each Xeon is a quad core, so in total he's got 2x4 == 8 cores at his disposal.

Yours is a Core 2 Duo - Core 2 indicates the second generation of Core micro-architecure and Duo indicates a dual core. So your machine has 2 core at your disposal. A core is a physical processing unit.

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