Vanilla: You can already have 10Ghz CPU at Apple (Quad 2,5Ghz G5), so we are really above that.
Even Intel is next to it with their DualCores which only need 2 Cores to get next to the 7Ghz :-)
If you're talking about the figure, the MHZ:
Four 2.5ghz processors right? they're running on.... 2.5ghz clocks.
Four 2.5ghz processors still run at 2.5ghz. adding a new processor doesnt add more clock speed. It also doesnt add an async clock running with the original. You remain with one clock. 2.5ghz.
So what you acually have is a 2.5ghz computer still, not 10ghz. :P
As Gabriel said:
Performance should never be measured in clock speed,
[edit]
Whoops, Old thread!
Sorry- seeing people refer to dual processors as double the speed in MHZ is a pet peeve of mine! :P