Clock Speeds Explained
Using an Athlon XP 2400+ Thoroughbred as an example, this CPU runs at 1995MHz. To get this number, a combination of a specific Front Side Bus (FSB) setting and a specific CPU Ratio (Multiplier) is used. Officially, the Palomino and Thoroughbred launches sported 133 FSBs, whereas the Barton supported 166 FSB. Later on, both the Thoroughbred (TBred) and Barton supported faster FSB speeds, but we've covered those topics in our CPU reviews. Now, depending on which class of CPU you had(ve), your CPU will have a multiplier that determines "what" times "what" equals "what". Therefore:
CPU Ratio (Multiplier) x Front Side Bus (FSB) = Clock Speed
In the case of the Athlon XP 2400+, it is 15 x 133 = 1995MHz. For a Barton 2500+, it is 11.5 x 166 = 1909MHz. Both CPUs have similar clock speeds, but use different settings to get there.
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