As per the CEO of Nokia, i.e. Stephen Elop, multi-core processors viz dual-core and quad-core processors are simply a waste of the smartphones battery life and are hardly of any use to their users.
Off late, Nokia has been on a marketing campaign called the “Smoked by Windows Phone” or “Blown Away by Lumia” as it is called in India, wherein the Windows Phone based Lumia phones are made to compete with any other smartphone using day to day applications and have proved to be equally or even more efficient than these multi-core processor equipped smartphones as per Elop.

Nokia has been gunning away other handsets with their Blown Away by Lumia campaign in various countries including India wherein they are giving INR 1000 if any smartphone is faster than the Lumia in day to day applications. A similar campaign has been started in China as well.
Interestingly, according to Elop, Windows Phone has never lost any of such campaigns to any other handset. So at the end of the day Elop is trying to indicate that the performance of a handset isn’t really linked to the number of processors embedded in the smartphone.
Well, we can only wait and see till dual core processor based Windows Phones are launched by Nokia. And then it would be very interesting to hear what Mr. Elop has to say.