Alan,
I am fairly confident both the X2 and the Conroe will be clocking somewhere between 2.8Ghz and 3.6 Ghz
My expectation is 2.8 to 3.2 GHz, with AMD ahead in raw clock speed.
In terms of relative performance, I'll predict that on existing applications it will be very similar per clock, but on newly compiled applications (AKA spec) Conroe will be ahead. I think the "fourth pipe" and the new fused macro-ops will require new code to really shine.
It is possible Conroe will be ahead. There may be ways to get further advantages by compiler tricks, but I suspect that where it is possible, the advantage will be there in the existing apps that were not re-compiled. I am assuming that Intel is enhancing the algorithms for scheduling of instructions, and there will probably be more instructions in-flight.
My expectation is, that unlike the odd-ball Netburst processors, that were very picky, and unfreindly to old code, I think Conroe (like K7 and K8) will run old code just fine. Not just fine, great.
Joe