There have been some recent reviews of intels latest dual core engineering samples. If memory serves me correctly intel came in at a much lower clockrate than the current crop of Opteron solutions (FX-60) but in turn won the overall benchmarks comparisson between the two by a good margin.
I think they pitted the new intel (2.6ghz) against a 3Ghz dual core Opteron series processor. Although this is not a current technology comparisson it does show that intels upcoming chip solution is strong and should have no problems given AMD a good fight the money.
Nonetheless as things currently stand anyone investing in a XEON workstation or server should have there marbles checked