General Question about Dual-Core Processors

I have a question, in general, about all dual-core processors. My laptop uses an Intel Core 2 Duo processor and it says the clock speed is 1.73GHz. My friend and I were talking about game requirements the other day - Call of Duty 4 - and he said the minimum speed needed is 2.4GHz. After I told him the speed of my processor, he said that 1.73GHz is the speed of only one processor, so my overall clock speed would be 3.46GHz.

Is he right? Or is the speed of one processor only 865MHz, and the total is 1.73GHz? I was wondering if this kind of thing would also be the same for quad-core processors.

Edit: Does anyone know if Call of Duty 4 would work on my laptop?

Processor: Intel Core 2 Duo T5300 (1.73GHz, 533MHz FSB, 2MB L2 Cache)
RAM: 2GB DDR2
Video Card/RAM: Intel GMA 950/ 256MB (probably shared)
Screen Res.: 1280x800 <--does this make a difference in the speed of the game?

neither is correct. Both run at 1.73 GHz, but they are independant, it isn't the same as a single core with twice the speed. Core 2 Duo's will be fine running this game, however your graphics card with really struggle.

Not to be a downer, but CoD4 will not work well on your lappy (if at all). The Intel Integrated series graphics cards are built for power saving, not performance. Your CPU and memory are fine, but there's just no way with your video card, unless maybe running it at minimums at 800x600 or another low resolution.

And resolution (1280x800, etc.) is how many pixels are shown on yoru monitor, so a lower res will mean less pixels, which is less stress on your video card.