Upgrading a processor

[idata]

Hi,

There is something unclear to me about processors.

Right now I have a Core 2 Duo e6600 which has 2 cores at 2.4 ghz. What if I decide to buy a i5-750S, which has 4 cores at 2.4 ghz, will my computer run twice as fast?

and what does number of threads mean?

If someone could explain me the concept of measuring CPUs by speed I would be grateful.

Thanks!

[idata]

It will depend on what you want out of your system.

[idata]

I just want my system to be fast, but I need to know how much fast If I get a CPU

[idata]

is the formula of calculating the performance of a cpu (cores x clock speed) ?

[idata]

You do know you can't upgrade the CPU from a e6600 to a i5-750S right? The i5 needs DDR3 ram and a new motherboard to support.