Monday night AMD finally launched Barcelona, its first quad-core chip, the save-the-company device that proved harder to build than AMD thought it would, costing it critical quarters in the marketplace, months that have paid off nicely for AMD's giant rival, Intel, which has been selling quads since November.

AMD lost time - 12 points of market share - and close to $2 billion because it had its heart set on producing a true x86 quad on a single die, not two dual-cores squished together like Intel makes. The time it took has made AMD rue it didn't take Intel's approach.

But it's here now as the two-socket Quad-Core Opteron touted by AMD as the "most advanced x86 processor ever made" and a "microprocessor milestone" with OEM systems coming from HP, Dell, Sun and IBM. White boxes will follow.

Intel, however, still claims the lion's share of the performance, performance-per-watt and lowest watt benchmarks.

AMD claims the edge on SPECfp_rate2006, SPECint_2006, SPECCompM 2001Base, STREAM, Fluent and LS-DYNA, a relatively narrow field of mostly non-commercial benchmarks that the Opteron typically excels on but not enough this time to make Intel eat its dust. Heck, in some of these cases it'll be eating Intel's.

Having previously challenged the clock rate metric that Intel drummed into everyone's head as the standard, AMD now says quad computers should be judged on the basis of an average CPU Power (ACP) metric that it dreamed up that represents processor power usage - like cores, integrated memory controllers and its proprietary HyperTransport links - while running a suite of commercially useful high-utilization workloads.

It's supposed to be more indicative of the power consumption that end users can expect. AMD says it's a useful metric for data center operators when estimating power budgets to size their data centers.

The company will still publish what it calls TDP or thermal design power metrics, a gauge it previously invented to show how much power a CPU consumes in rare worst-case scenarios.

AMD rates the Barcelona chips it has now at 55W and 75W on this new ACP metric, which AMD presumably hopes will distract people from noticing that Barcelona - in terms of clock rate - is available initially only at speeds that are less than expected - to wit 1.7GHz-2GHz while Intel's fastest Xeon is 3GHz.

AMD is promising increases to an architecture-validating 2.3GHz in Q4, but perhaps not before Intel produces a second-generation quad in November.

The delay in delivering a high-end device may be because AMD hasn't got all the kinks ironed out.

So, to be clear, AMD has only 75W standard and 55W energy-efficient Barcelonas available now. In the standard category, a 1.9GHz chip goes for $316 or $786 in quantity depending on whether it's a two-way or eight-way chip while a 2GHz is priced at $389 or $1,019. There are energy-efficient models available at 1.7GHz, 1.8GHz and 1.9GHZ priced at $209, $255 and $377 respectively in quantity.

It is unclear how AMD's 75W would translate into Intel-speak but a 3GHz top-of-the-line Intel quad Xeon X5365 consuming 120W goes for $1,285 in volume.

Meanwhile, needing to make up for lost time, AMD is promising quad Phenom desktop processors in December. Intel's desktop quads should be out in November.

Playing to the green movement, the widget includes AMD's CoolCore Technology and so unused parts of the chip can be turned off to save energy and the clock rate of each of the cores can be adjusted to application requirements. The cores and memory controller also operate on different voltages determined by usage, another power-saving technique.

AMD is positioning Barcelona as an ideal virtualization platform because of its integrated memory controller and also because of its newfangled Rapid Virtualization Indexing, AMD's way of reducing the overhead associated with software virtualization.

Rapid Virtualization Indexing takes functionality that was previously done in software and accelerates it by doing it in the CPU, a method said to enable near real-time application performance.

Barcelona fits existing motherboards used by dual-core Opterons making the upgrade to the quad design easier for server merchants.