Quad cores defined
Clear as mud now
By: Charlie Demerjian Saturday 04 November 2006, 08:23
WE ARE ABOUT to enter a PR battle of epic proportions about quad core. No, not performance, abilities, price or anything else real, just over the definition.
Intel says it has a quad core first, and AMD says no it doesn't. Intel says it is selling a real quad core and AMD says it not. Both are right in both cases.
The crux of the argument is simple, Intel's quad core parts are two Woodcrests on a slab of fiberglass, and the two dice are separated by almost a cm of space. Single chunk of silicon they are not. If asked, Intel will tell you that any customer buying a Kentsfield or Clovertown will have four cores under a heat spreader, and 99.999% of them will never take that off, so functionally it is a four core. You buy it as such, you plug it in as such, and it operates as such.
AMD will laugh and point to Barcelona and say that Intel has a nasty hack. Your chunk of silicon has two cores on it or it has four. Your bus sees it as one load or two. It is that simple.
So, which one is it? Well, both and neither. My definition is quite simple, does any core have to go out across the bus to talk to any of the other cores? If so, it is not a quad core part. Does it matter to the consumer? Not a bit, this is only a strictly technical definition.
If people buy a box that says 'contains four CPUs, it is just that, it has four cores. If it is one or two chunks of silicon under the spreader, who cares? Does it perform? If so, then the layout is totally irrelevant. Kentsfield does perform, and you can see four cores under Task Manager. Could it be a few per cent better if it was on a piece of silicon? Probably, but who cares?
So, from a functional perspective, Intel has a quad core part. From a technical perspective, it doesn't, and AMD will be the only one to have that for over a year. Geeks debate the technical perspective, people buy on the functional perspective. That is the end of that, right?
Not so fast my fine asocial friend, there is another wrinkle to this. If you buy the Intel functional argument you basically buy a box and it does a job, so where does it leave 4x4? You buy a box with four cores in it, it is sold as one piece, and has four cores in Task Manager. 99 per cent of people will never open the box other than to see what they bought, so for all they know, it could be magic beans powering the thing. Windows says four cores.
So, if you buy the AMD view, no one has four cores until Barcelona launches. If you buy the Intel view, it was first, but AMD will be less than a month behind. Your call. In any case, Sun can laugh at them all, it has had eight real cores by either definition for over a year, and IBM has done the MCM thing to more than that. Intel and AMD both lose. µ
