It doesn't really work like that. A dual core processor is a single processor with 2 cores on it - before you needed 2 physical processors to get a 2nd core. But you can't just add the 2 speeds up and say that's your speed. Most programs will only run on one core or the other for a total of 2.3GHz. SOME programs are multi-threaded which means they will split up their work (somewhat) evenly between the cores.

A dual core processor essentially functions like TWO processors working in tandem. Instead of having to switch between tasks, it can actually perform TWO tasks simultaneously (more if there are other technologies involved).

The "running at 2.3 GHz" part means that the base clock of your processor is 2.3 GHz. The "dual-core" part means that the physical processor chip contains two separate execution cores. This allows the processor to perform two operations during the same clock cycle. Unless your software is written to take advantage of this (and Windows is somewhat), this won't double your speed. The problem is the input/output pathways to the processor will act as a "bottleneck" and limit the ability of the software to take advantage of the dual cores unless there are two separate paths to your memory (and some motherboards will support this). These problems (and many other factors) have caused all major chip manufacturers to try to de-emphasize the clock speed of their processors. AMD is calling their new offerings by their rev and core numbers and Intel has started an "i" naming scheme (Core i7, Core i5, etc). Hope this helps.

You're almost right... in a dual-core processor there are in fact 2 complete processors operating completely independently, but I think most people would think of them as operating in parallel rather than tandem. In an ideal (and usually quite unachievable) situation, they can do as much work as one 4.6 GHz processor. This ideal is rarely if ever achieved. First, code is required to schedule the 2 processors, over and abocve the code required to schedule a single processor, and second, two processors can only be kept busy if the workload provides work for both processors. This is usually not the case. Most software is written without thinking about multiple processors, so it is common to see a combined load around 55%. The overall effect is equivalent to about a 2.5 GHz processor. Multitasking is the process of maintaining multiple programs/threads at the same time and allocating a processor to each thread in turn to maintain the illusion of continuous execution. A simple example is editing a word document, browsing a web site and printing at the same time. Multiple processors are not required for multitasking, but they do allow for smoother multitasking and will stop one rogue process interfering with all the others.