Chipmaker AMD is preparing to start shipping its 'Barcelona' processor to manufacturers in August. The first systems powered by the new quad-core Opteron processor are scheduled to start shipping in September.

The announcement marks an end to rumours suggesting that the launch was delayed, but failed to completely silence all critics.

The chips shipping in August run at clock speeds of up to 2GHz, and faster models are not scheduled to arrive until the end of this year.

Intel, by comparison, is shipping Core 2 Quad Xeon processors codenamed Clovertown at speeds of up to 2.66GHz. AMD's current dual core Opteron max out at 2.8GHz.

AMD has previously boasted that Barcelona will allow it to take back the performance per Watt lead from Intel.

But it "remains to be seen" if AMD will be able to deliver on that promise, Nathan Brookwood, an analyst with Insight 64, told vnunet.com. "This is not as fast as people had expected from a clock frequency standpoint," he said.

AMD also did not release performance benchmarks for the processor, although the chipmaker is maintaining that the chip will outperform Intel's Clovertown.

Brookwood cautioned against reading too much into the absence of those metrics. Although it could indicate that the AMD chip failed to pull ahead of its Intel rivals, AMD also could save the data to stir up excitement when the chip starts shipping.

The four cores on AMD's processor are all manufactured on a single die, which is referred to a monolithic design.

Intel's quad-core uses two duo-core dies packaged together in a single chip. The AMD design allows all cores to share the same set of cache memory, which offers increased performance in certain applications.

None of the current benchmarks, however, will demonstrate the benefits of AMD's design over Intel's. Brookwood suggested that only real workloads will be able to show users which chip has the best performance.

In addition to expanding the number of processor cores, the AMD chip also introduces L3 cache memory, which will especially benefit database performance.

The chipmaker repeated a previous benchmark that showed a 70 per cent increase in the chip's performance and 40 per cent gain in floating point applications.