Cinema 4d & iMac duo vs. iMac quad...

Hey guys,
Need some input. Just purchased the new 27 inch iMac duo core 3.06. Went in to the Apple store with the intentions of buying the quad core i5, but was talked out of it by an apple sales person. I told him i needed it for some Cinema 4D work. He said Cinema dosen't use all four processor's in the i5 and that I would be fine with the duo core. He said my render times wouldn't be that much faster for the extra $300. Any thoughts? Is he right? Should I go with the quad core?
Thanks.

He said what?

He's wrong. It will render way faster in Quad core format.

Not a comment, question or suggestion about the forum. Moving appropriately.

ZorroAMG is right. Cinema 4D is one of just a handful of programs I know of that is thoroughly multi-processor capable. In this instance, a quad-core would really benefit you.

Also, over time, Mac developers should start to use the Grand Central development platform and OpenCL technology. The more they jump on that bandwagon, the more you'll benefit from having more cores. Seeing as Maxon has a track record of early implementation of SMP technologies, your capabilities only stand to grow.

Thank You guys! I guess I will be returning to the Apple store.