PC processor, which is better?

Performance of the processor doesn't depend on it's core speed.(eg;- 2.4 GHz or 3.0Ghz).

It really depends on which core is used in the Processor.

For an example :- though Core 2 Duo E6400 2.0GHz and Core 2 Duo E6420 2.0Ghz have same speeds E6420's performance is betterthan E6400 because E6420 has a "conroe" core and E6400 has a "Allendale" core.

However,

Dual core processors have a huge performance than single core ones (even with dual core ones which has a less core speed) when it comes to multitasking.

You can get a better idea from this

http://www23.tomshardware.com/cpu_2007.html?modelx...

Not quite; the speed boost from dual core needs to be supported by the OS first, and then you need to take into account that one dual core processor isn't quite as fast as two physical single core processors, for the simple reason that the two cores share more components.

I've heard anything from multiplying by 30% to 100% quoted, so I'd take it with a pinch of salt.

Also don't forget that the efficiency of the core itself will be a factor. AMD processors are great all-round performers, and are faster 64-bit processors than Intels. Intels have better floating point performance, however. And lower-cost options (such as Transmeta and VIA) are not necessarily such great performers, but might enable you to spend more on hard disk and / or memory, which will definitely have a positive impact on performance.

Dual core, even quad core doesn't mean the processor itself runs any faster. The clock speed is the same, 2.4Ghz is the same as Dual-core 2.4Ghz. The only difference being that the dual core can run many more threads and a single core processor, hence multiple programs run faster. (You can tell i'm not a computer whizz!)

Well having two cores shares the load, which can be both beneficial as its not putting as much a load on each core, and slower as it takes extra time to communicate between the two cores. So I'd have to say the 2.4 may be slightly better.

Why not go for a 1.8ghz dual core? There's not much difference in price, maybe $20 difference?

A dual core processor combines two independent cores in to a single Integrated circuit (IC). As each core independently implements optimizations such as superscalar execution, pipelining, and multithreading, so we get a better performance. And you have rightly pointed out that the capacity would be 2X i.e. 2x1.4 GHz for 1.4 GHz dual Core CPU.

The proceccors work at the same rate splitting the load and yes it usually is better to have a duo processor because it is double the power of a solo

it is not, nor has it ever been just about clock speeds.

its about the technology employed in the processor too.

for now the dual cores and quad core cpu's are a newer and faster technology than the older prescott etc cpu's .

you need to do a bit more reading.

heres some good starters.

http://en.wikipedia.org/wiki/Intel_Core

http://en.wikipedia.org/wiki/Amd

http://en.wikipedia.org/wiki/Cache

As above

The more ghz the better i say