How to find the CPU clock speed and frequency of a Solaris server

Use this command:

/usr/platform/`uname -i`/sbin/prtdiag

In our Solaris E2900 Server following is the excerpt from the output which shows CPU frequency as 1350 MHz and clock frequency as 150 MHz.

System Configuration: Sun Microsystems sun4u Sun Fire E2900
System clock frequency: 150 MHZ
Memory size: 96GB

======================================= CPUs =======================================
E$ CPU CPU Temperature Fan
CPU Freq Size Impl. Mask Die Ambient Speed Unit
------ -------- ---------- ------ ---- -------- -------- ----- ----
SB0/P0 1350 MHz 16MB US-IV 3.1 82 C 35 C
SB0/P1 1350 MHz 16MB US-IV 3.1 81 C 35 C
SB0/P2 1350 MHz 16MB US-IV 3.1 78 C 34 C
SB0/P3 1350 MHz 16MB US-IV 3.1 80 C 34 C
SB2/P0 1350 MHz 16MB US-IV 3.1 77 C 35 C
SB2/P1 1350 MHz 16MB US-IV 3.1 78 C 36 C
SB2/P2 1350 MHz 16MB US-IV 3.1 83 C 37 C
SB2/P3 1350 MHz 16MB US-IV 3.1 82 C 37 C
SB4/P0 1350 MHz 16MB US-IV 3.1 66 C 32 C
SB4/P1 1350 MHz 16MB US-IV 3.1 73 C 34 C
SB4/P2 1350 MHz 16MB US-IV 3.1 84 C 38 C
SB4/P3 1350 MHz 16MB US-IV 3.1 74 C 33 C

prtdiag can be executed by any user and doesn't require root privilege.