At 2.2 GHz, the Opteron 248 is just as fast as the soon-to-be-released Athlon 64 FX-51 and given the performance numbers we've seen from that chip (sshhh) could be a real monster of a product.
Opteron's single CPU performance is strong, but it's the chip's ability to scale that has always been one of its core strengths, as adding an additional Opteron can boost performance as much as 90% in applications that are traditionally bandwidth-limited on a standard SMP configuration.
Releasing a 2.2 GHz part so quickly after their 2 GHz implies that AMD may have finally turned the corner on whatever yield problems they've experienced and be gearing the Athlon 64 and Opteron architectures up for a real fight. µ