From the C8051F0xx datasheet (rev. 1.4, page 112):
"Data can be transferred at up to 1/8th of the system clock ..."

Given the maximum system clock frequency of 20MHz, this gives you a theoretical maximum speed of 2.5MHz for the SMBUS.

Fast enough, I think ... ;o)


Rob.

P.S. When posting the same question on more than one forum, please say so in your post, so that others don't needlessly post the same answer twice.