in Apple's support forums discusses complaints of crippled clock speeds after installing yesterday's SMC firmware update on Intel Macs. Upon an apparently successful update, some users checked their min and max clock speeds with CoreDuoTemp
to find that their max has been limited to 1000 Mhz, even after using utilities to force their machine to work as hard as it can.
I just used CoreDuoTemp to check my own MacBook Pro's clock speeds to find that it's max is set right where it should be, at 2000 Mhz. However, if your Intel Mac's speed is suspect after successfully installing yesterday's SMC firmware update, check out this forum thread
to see if something is really afoot in the land of Intel Mac clock speeds.