There is no Q2600, you must be on about the Q6600.
Higher mhz is better but the latest generation are much more efficient so a Core 2 at 2.0Ghz will beat an old P4 at 3.0Ghz.
So does the numbers have any relevance to the speed? - would a Q2600 have 4 processors all running at 2600GHZ or am i missing the point
if so would that make it a 10400GHZ
Yes all the cores run at the same speed, for the Q6600 this is 2.4Ghz, but no it doesn't make it the equivalent of a single 8.6Ghz core, because not every application is able to use 4 (or even 2 cores).
It's only 4 times as fast in certain applications, some encoding/rendering software, WinRAR, certainly not games or Windows.
Unfortunately the numbers don't have an easy link with the clockspeed, but for Intel it goes like this
E2xxx - budget dual core
E4xxx - not-so-budget dual core
E6xxx - expensive dual core
Q6xxx - quad core
TBH for a typical 'home user' you may as well get the cheap E2xxx series, you wouldn't notice having 4 cores apart from the 100 extra notes missing from your wallet lol.
I think the Intel chips are not true 'quad' cores but simply 2 dual cores banged together in the same CPU, thus a quad core of a sort.
(I may be wrong though!)
They are still very fast and the top end beat AMD,s genuine quad core but cost far far more coin.
You're right mate.