For specific workloads, Itanium is great. It can sustain 2 FP loads, 2 FP stores, and 2 FMA's in a cycle, which means for certain types of DSP-ish workloads, it has more performance per-cycle than just about any other mainstream CPU. It also has a very high-performance cache hierarchy, with massive blobs of SRAM and a low-latency L1 (one cycle to access.) The problem is that it's expensive, clocked low, and not really ideal for where it's marketed (the mission-critical enterprise server business.) It still has significant advantages over Xeon for some workloads, namely things that are highly cache-sensitive or that scale high enough where directory-based coherence is good to have.