IT managers will likely see the biggest value proposition, however, in Suns upgraded support for mixed generations and speeds of UltraSPARC IV+ and UltraSPARC IV CPU boards in the same server. During tests, Suns CPU/Memory Uniboard technology and the binary compatibility of the Solaris 10 operating system allowed us to run an UltraSPARC IV-based Uniboard simultaneously with an UltraSPARC IV+-based Uniboard. In addition, we were able to swap the UltraSPARC IV-based Uniboard and replace it with an UltraSPARC IV+-based board with no problems.Suns support for heterogeneous processors and speeds will allow IT managers to run a combination of CPUs as their organizations computing needs gradually grow and change, avoiding forced migrations.It also will enable administrators to run Solaris 8 on the UltraSPARC IV, as the UltraSPARC IV+ platform supports only Solaris 9 and 10. Users will see the biggest performance boost when running Solaris 10, whose container and Dynamic Tracing capabilities can leverage the power of the new chip. When retrieving systemwide diagnostic information using Dynamic Tracing, for example, we noticed a significant reduction in the time it took for the UltraSPARC IV+-based Sun Fire V490 to complete the task versus an UltraSPARC IV-based system. Sun estimates that users will get as much as 3.5 times the throughput from the V490 with the dual-core UltraSPARC IV+ processor over UltraSPARC III-based systems. Next Page: Stiff competition.