Did you make sure to update your dual core drivers first? I had the same problem, and updating the drivers then the optimizer fixed it.
First try updating the drivers and then installing AMD's optimizer from
here. If that still doesn't work, then do the following(in WinXP):
Open 'Task Manager' (right click in the taskbar)
Go to 'Processes' tab
Right click on the RTW process - the name has slipped my memory and I'm at work :-(
Choose 'Set Affinity...'
Uncheck 'CPU 0'
Click on 'OK'
Congrats, its done.
As to the origional question, I would assume that if I got my AMD dual core to run well(7000+, all high settings, no lag) then an Intel would work the same way. But if worse comes to worse you can always disable one of the CPUs.