Quad core slower than Dual core with same application?

[vwgolfman]

I use my machine for both gaming and running business applications.

Which CPU would be better; a Core 2 Quad 6600 or a Core 2 Duo E6750/6850?

If I use the Quad core with an application which doesn't utilise it is it likely to run slower than the same application with one of the Dual cores?

Many thanks for any advice.

 

[Emlyn_Dewar]

Unless you clock the quad core so it's core speed equals that of the dual core, it would run slower.