Meet the Barton family
The "Barton" chip we're looking at today is dubbed the Athlon XP 3000+. Because the Barton core offers higher clock-for-clock performance than the Thoroughbred, this chip gets a "3000+" model number, even though it only runs at 2.166GHz. At that same clock speed, the T-bred only gets a 2700+ rating. This situation leads some much-needed confusion to the formerly clear-as-a-bell AMD model number rating system.

Thank goodness.

But the real kicker is the 2800+. As I said above, AMD introduced the 2800+ last October as a 2.25GHz T-bred chip, but they never became widely available. Now, the T-bred-based 2800+ is being laid to rest, replaced by a Barton chip running at 2.083GHz, also with a 2800+ model number. AMD now says the T-bred-based Athlon XP 2800+ was a limited-production part, and its days are over. If you want a 2800+, you've gotta go with Barton.

The cheapest Barton will be the Athlon XP 2500+, clocked at 1.83GHz. AMD released 2400+ and 2600+ T-breds at higher clock speeds, but the 2500+ model number is distinctive. Like all Bartons, the 2500+ runs on a 333MHz front-side bus. (By the way, AMD says it's evaluating the possibility of moving to a 400MHz front-side bus. It's possible the faster bus speed could debut alongside the Athlon XP 3200+ in the middle of this year.)

In something of a departure for AMD, these new chips won't come cheap—especially not the Athlon XP 3000+. This puppy will weigh in at very healthy $588. I can't remember the last time a top-end AMD chip cost that much money, but AMD seems to be emboldened by its model number system. Since introducing the ratings, the company has been progressively less shy about pricing its chips near comparable Intel products. Then again, AMD might be pricing this chip so high in order to limit demand and stave off potential shortages of these high-end parts.

Or maybe they got greedy and decided turning a profit for once might be nice.

Whatever the case, the Bartons will have their work cut out for them. The $588 3000+ model is a little cheaper than Intel's P4 3.06GHz, which is currently selling online for about $630. At $375, the list price for the 2800+ is higher than the current street price of about $370 for the Pentium 4 2.8GHz. And the 2500+ will list for $239, again a little higher than the competing Pentium 4 2.53GHz, which goes for about $230 online. Fortunately, the 3000+ and 2800+ variants should be available—for real—right away. AMD says the 2500+ will appear by the end of the first quarter.

Of course, the benchmarks will tell the story of whether these chips are worth this kind of bank/cash/jack/wampum/bling-bling. And those are up next. But first, let's have a quick peek at our T-bred versus Barton photo spread.

Visually, not much has changed except for the length of the chip itself. The packaging of the two chips is identical.

Now, on to the tests.