The firm says the Barcelona will be 50% faster in floating point applications and 20% in integer performance.
The clockspeeds of the Barcelona processors weren't released. Intel's quad-core Xeon is currently available at 2.66GHz but limited supply of a 3GHz is already available.
AMD promises a lot, but we would prefer to see some real chips and real benchmark data.
UPDATE: More details about the benchmark AMD used.