Sun designed the chip this way because server workloads usually have high re-utilization in data and instruction across processes and threads but low number of floating-point operations in general. Thus sharing hardware resources among the four cores in a cluster leads to significant savings in area and power but low impact to performance.
Sun designed the chip with this architecture because server workloads typically exhibit high re-utilization of data and instructions across processes and threads but relatively few floating-point operations. This leads to substantial savings in hardware resources when shared among the four cores in a cluster, resulting in reduced area and power consumption with minimal impact on overall performance.