IBM published Barcelona SpecCPU results.

[onewingedangel]

K10 performance raises around 5,5% with only 100mhz.

2.0/1.9= 1.0526.....

so a 5.3% increase in core clock results in an equivilent increase in performance, colour me suprised

When core clocks are so low of course the percentage gain is going to be great for small increases in clock, as core speeds increase each 100mhz results in a lower percentage improvement.

100 to 200mhz results in 100% improvement
1900 to 2000 just over 5%
2900 to 3000 just under 3.5%

Its only when I/O is a bottleneck that you'll see less than ideal scaling, and at low speeds theres certainly not going to be a bottleneck. If we were talking about the highest end parts then the fsb would probably provides some problems with scaling, but going from 1.33 to 2.66 to 3ghz sees a similar increase, so IO doesn't seem to be a bottleneck.