Quad Core explained (SM article)

[Lincoln]

As a follow-up to our hugely-popular Dual Core explained (http://www.short-media.com/review.php?r=261) article, Rob "Thrax" Hallock has written Quad Core Processing: Over-simplified, demystified, and explained (http://www.short-media.com/review.php?r=346), which I think is an even BETTER read. :cool:

Quad core is the future, and it's a future that's coming faster than the dual core one did. While few developers reacted quickly to the introduction of dual core CPUs, (perhaps unready for such a drastic change), developers have begun acting on quad core even before there was a chip to test it on. Valve Software (of Half-Life 2 fame) and Remedy Entertainment (of Alan Wake fame) both began work on optimizing quad core code before the Kentsfield had even finished production on the very first processor. This time, developers have had fair warning, and the good sense to read the writing on the wall.

Whether or not you're a nuts-and-bolts technophile, I think you'll really enjoy this piece.

Digg it! (http://www.digg.com/hardware/Quad_Core_Processing_Over_simplified_demystified_and_explained)

[Winfrey]

Great job Thrax! It was a nice read for late night keepers like myself.

...dug!

[Leonardo]

Well done! Practical, to the point, and just enough history to provide pertinent background and perspective. Fires right at center of mass of the computing audience.

[CyrixInstead]

Did you make the pretty pictures Thrax?? Good article.

~Cyrix

[Thrax]

I made all the pretty pictures. ;D

[airbornflght]

Great Article Thrax. I would have dugg it, but I'm not registered, and I have to leave for school.

[Thrax]

Jerk!

[lemonlime]

Awesome writeup, Thrax :cheers:

[Sledgehammer70]

Quad is the power of tomorrow

I feel inspired.... awesome article :)

[profdlp]

Very informative and well written.

Nice job. :)

[QCH]

:thumbsup: Nice work :thumbsup:

[mirage]

I was going to tell Thrax that it is awesome job :thumbsup: :thumbsup:
... but should this correspond to Panties now ?

Dug !!!

[javipas]

Nice review, though now that we've got Quad FX with us maybe you should update your views. There's little mention of Quad FX (4x4/QuadFahter) on your text, and it has been demonstrated that AMD has been obliged to offer something quickly to be able to offer an alternative to Kentsfield.

The approach is, as you should now, "inelegant" as well, and though most of the people see this plattform as interesting for the future (you're able to use future 2xQuad-cores, having an eight-core machine through two Socket 1207), I can't see the reason for that, other than having an option for a very tiny percentage of users.

Otherwise, stick with your current processors or buy Conroe/Merom until the real Quad-Core (Altair FX, etc) comes on Q2/Q3 2007.

[Thrax]

Quad FX is not quad core. The purpose of the review was to specifically address <i>quad core CPUs</i>, not stop-gap responses by a company that is losing the battle (Sadly). I'm a big AMD fan, but I could not justify the inclusion of their product in a quad core CPU explanation, because it's just not quad.

-Thrax

[javipas]

Quad FX is not quad core.

I beg your pardon. Quad FX IS quad-core. Not pure, not native, but it's quad-core. The article speaks about inelegant and native approaches, and both Kentsfield and Quad FX are the inelegant ones. Yorkfield and Barcelona will be pure/native quad-cores.

I'm too a big fan of AMD, and I agree with you on AMD's early effort to "fill the gap" - a gap produced by Intel trying to anticipate native AMD quad-core - Let's wait for K8L. But until then, it's clear who's the winner.

[Sledgehammer70]

So you’re saying the server market with 2 Dual core Opty's should be called Quad cores also? I personally have a few dual - dual core Woodcrest systems on the server side, so those also could be compared as Quad core setups in your logic right?

I think Thrax's goal was to give a overview of 1 chip with 4 cores under one hood. Rather than a server type of setup with 2 chips running 2 cores each. Which is what 4x4 systems are doing.

[Thrax]

Quad core. Four cores, one package, CMP for load-balancing.

Two CPUs is SMP. Period. It may have four cores, but it isn't quad.

[Sledgehammer70]

Quad core. Four cores, one package, CMP for load-balancing.

Two CPUs is SMP. Period. It may have four cores, but it isn't quad.

Hence why they are called Dual socket Dual core systems :) If javipas theory was true we would have had Quad cores for many years now.. even dual Octuple systems :)

[javipas]

IMHO when you use two dual-core CPUs you get a four core system. Thrax has made it clear in the article, it's an inelegant solution, but it has four cores. So yes, basically one could have named those 8-way systems "octo-core" if they'd have wanted. It's just a name, and after all, we always can tell that this is not true quad-core, as Presler wasn't true dual-core either.

And by the way, Quad FX isn't SMP. It's NUMA. Each processor has access to their two banks of memory, something than differentiates this schema from SMP. (wikipedia - smp)

[Leonardo]

IMHO when you use two dual-core CPUs you get a four core system Yes, but the article was NOT about four-core systems, but rather four-core CPUs. :)

[Thrax]

That's incorrect. SMP is symmetric multiprocessing, which is any two or more processors (Physical) running in parallel. The Athlon FXs <i>themselves</i> use NUMA <b>as</b> an SMP computer. NUMA is just a memory access method.\\

Your opinion about what quad core is and isn't is fine, but the simple fact of the matter is that only CPUs with four cores in <b>one package</b> is a quad-core chip. Just like two single-core CPUs weren't dual core.. They were SMP processors, nothing more, nothing less.

Just because it has four cores doesn't mean it's quad core. The quad core technique <b>must</b> employ Chip Level Multiprocessing (CMP) across four cores to qualify as a quad core part.

[javipas]

I'm starting to think we're talking about two different things: I agree with you people in almost everything!!

But again, even Thrax has said what I'm talking about: Kentsfield and Quad FX are inelegant quad-core processors. That's all.

Intel is poised to strike first, preparing to release the Kentsfield, the first quad core desktop processor.

You can argue that Kentsfield uses MCM (Multi Chip Module) to join two dies (Conroe) in one packaging, but as we'd say in Spain, thats a 'chapuza', (shoddy piece of work). And AMD's proposal is quite the same.

[javipas]

Thrax, I think you and I (I think exactly the same, those are no true quad-core CPUs) would have a hard time trying to explain that to AMD/Intel guys.

[Leonardo]

Thrax, I think you and I (I think exactly the same, those are no true quad-core CPUs) would have a hard time trying to explain that to AMD/Intel guys. Fortunately I'm a Via guy, so I understand it all!

[Thrax]

Thrax, I think you and I (I think exactly the same, those are no true quad-core CPUs) would have a hard time trying to explain that to AMD/Intel guys.

Good thing for us I don't write about marketing. :D

[javipas]

Me neither ;-) I do write on a spanish mag/online site too and I've never dared to tell Intel/AMD that kind of things. Yup.

[Thrax]

A small blurb from AMD's press release:

AMD Quad FX Platform with Dual Socket Direct Connect (DSDC) Architecture, the first dual-socket, multi-core desktop PC platform

[javipas]

Good for them. They call things by their names.

[danball1976]

Oh, and according to that article, an owner of an AM2 board that was designed for dual core can run a quad core processor with just a BIOS update. Is that really true?

[Thrax]

That is what AMD is saying; subject to change, of course.

[danball1976]

I don't know, that just doesn't seem believable. I would think that such a CPU upgrade would require a new motherboard. Most AM2 boards have a 4 phase power supply, so I think that plopping in a non energy-efficient quad core processor and expecting it to run would be less than successful

[Thrax]

The Barcelona will use 65nm, as opposed to today's 90nm. The thermal output is expected to be identical to today's dual core Athlon 64s due to that die shrink. Barcelonas use identical voltage to today's dual core Athlon 64s. They also use the same socket.

It's very believable, you just have to stop and look at the technical specifications for a moment.