The Q6600 cpu has supplied to it via the mobo a clock speed of 2.4ghz.
Effectively the 2.4ghz is the rate each core of the processor runs at.
4 x 2.4ghz = 9.6ghz.
IF it was a situation where each of the cores contributes to the work of the cpu as a whole, i.e. u run SuperPI and all the cores worked on it, the efficiency vS a standard single core cpu would be equiv to it operating at 9.6ghz.
Either way you look at it, the mobo only supplied the cpu with 2.4ghz (unless overclocked of course) so the rating of the processor is 2.4ghz. It`s the clock speed of the cpu.
The clock speed of the processor is a factor of the mobo`s fsb. This fsb is constantly ticking over, as this effective rail ticks over, the cpu uses it to nudge forward instructions for execution. Even if the processor had 8 cores and 2.4ghz was the clock speed, it may effectively be possible to execute commands, or do a job, at 8x2.4ghz (relative to a single core cpu of the same build), but inherently the clock is always 2.4ghz.
Software just isn`t up to the standard where u can say "9.6ghz" and even if u did, it would be missleading because the clock IS still 2.4ghz, across 4 cores. (there are rare programs that use the cores well, but even so).
Confuzed ?