Microprocessor comparison

The following table compares key aspects of different IBM® microprocessors.

Table 1. Processor Comparisons
  POWER3 RS64 POWER4
Frequency 450 MHz 750 MHz > 1 GHz
Fixed Point Units 3 2 2
Floating Point Units 2 1 2
Load/Store Units 2 1 2
Branch/Other Units 1 1 2
Dispatch Width 4 4 5
Branch Prediction Dynamic Static Dynamic
I-cache size 32 KB 128 KB 64 KB
D-cache size 128 KB 128 KB 32 KB
L2-cache size 1, 4, 8 MB 2, 4, 8, 16 MB 1.44
L3-cache size N/A N/A Scales with number of processors
Data Prefetch Yes No Yes