We had a privilege to see Barcelona K10 multimedia scores and we can confirm that clock to clock, it runs faster than Core 2 Duo. The big problem is how Barcelona K10 goes against Core 2 Duo at much higher speeds.
Instructionwise when you compare all known instructions K10 beats Conroe, there is absolutely no question about it. In 95 percent of cases K10 is faster clock to clock but the real issue is what happens to compare 2.5 GHz K10 versus Penryn at 3.4 GHz.
The other issue is that Penryn has more instructions including SSE4 while K10 has just subset of it.