What does C2D really mean?

I was sitting last night and my roommate asked me what kind of processor my mac had. I told him 2.16 Ghz, he then said that's kinda slow, I then told told him that it's actually 4.32 Ghz since it is dual core. He then went off trying to convince me that I really don't have two cores, My chip is named Intel Core 2 Duo for a reason! I told him that just because I have two cores does not necceraly mean it's twice as fast. He then tried to relate it to RAM... go figure. You know, that 1 GB is not 1000 MB, it's really 1024 MB, and that I don't actually get 2x 2.16= 4.32 Ghz it's more like 3 Ghz in total. I tried to show him, prove to him, explain to him, no dice. Tried to show him wiki, intel, apple, computing sites. nope he doesn't get it. If I am wrong, PLEASE tell me so I can apologize to him. If there is an app any shred of evidence that I am correct tell me show I can tell him. Any computer experts here?

To put it bluntly: yes, you're wrong.

Dual core does not mean you add the frequencies of each core (otherwise they would advertise it as 4GHz since Intel was doing great with the megahertz battle against AMD).

Dual core processors have to share system resources, which means RAM, front side bus, hard drive, etc. So this means the processor can't go twice as fast because each core only has half the resources. So yes, it'll go faster than a single core processor, but not nearly twice as fast. This is why the performance increase from the Athlon64s to the X2 processors wasn't that profound. Sure, they were faster, but marginally at best.

The reason why it seems that dual core runs so much faster is because we compare Intel's latest Conroe architecture (i.e. Core Duo) to its previous Netburst architecture (i.e. Pentium). The Netburst architecture was much slower than the current processors because of the way it was designed. A better comparison to prove that 2 cores does not equal 2x the speed would be between Intel's Core Duo and Core Solo lines as they share similar architecture.