If the stock GHz is higher, the higher you can OC it.
No! This is wrong and I will try and explain why.
For the purpose of making it simple we will look at the Core i7 900 series.
They had
Intel® Core™ i7-980 Processor
Select Intel® Core™ i7-960 Processor
(8M Cache, 3.20 GHz, 4.80 GT/s Intel® QPI) Launched Q4'09 130 W TRAY: $294.00
Select Intel® Core™ i7-950 Processor
(8M Cache, 3.06 GHz, 4.80 GT/s Intel® QPI) Launched Q2'09 130 W TRAY: $294.00
Select Intel® Core™ i7-940 Processor
(8M Cache, 2.93 GHz, 4.80 GT/s Intel® QPI) Launched Q4'08 130 W BOX : $555.00
Select Intel® Core™ i7-930 Processor
(8M Cache, 2.80 GHz, 4.80 GT/s Intel® QPI) Launched Q1'10 130 W TRAY: $294.00
Select Intel® Core™ i7-920 Processor
(8M Cache, 2.66 GHz, 4.80 GT/s Intel® QPI)
These chips are actually ALL THE SAME CHIP!
So say Intel designs the 940 processor and then starts pumping out thousands of them.
Due to the way these things are made they are not all equal.
So a 940 then gets tested with stock voltages and they increase these to each level set to test what the thermal output of each one is.
Based on a bunch of other variables they might decide that this 940 they made is just not up to snuff to handle being pushed at 2.93 Ghz with such and such a voltage so they bin this chip as a 920 @ 2.66Ghz
They might make the next chip and it is GOLDEN! it can fair exceed the previous processor specs of the 920. They make it a 940 it can run with stock specs at 2.93Ghz.
So basically what I am trying to say is that it is misinformation that a higher clock speed chip is going to clock higher than a slower speed chip. Cause in actuality the chip is already slightly overclocked in stock form.
Cuz they are all the same damn chip, they might have tweaks or different batches. For instance the Stepping. When the i7s came out there had g0 and b0 stepping the b0s ran a lot hotter than a g0. Thus Overclockers were all over getting a g0 so they could overclock them higher. Heat is one of the greatest limiting factors in overclocking.
So think of it this way
you have a room with a 10 feet ceiling
You have two men standing in this room.
One guy is 5'3" and the other guy is 6' 4"
You give them both stilts of 4' increase
The first guy is standing right at the ceiling, the other guy has to give up since his head would be through the roof.
I mean yes when you are talking processors it is possible for the 6 foot guy to go a bit past that ceiling, but it won't be much further, unless you need a shit ton of cooling to achieve it. Which is counterproductive to the fact you just spent 1k dollars on the 6 foot man and only $300 on the 5 foot man. When we talk Technology you always want to get the best Price:performance
A slower chip OC'd properly will give you that.
There are a lot of ins and outs of this concept, but the general rule always stays the same. If you don;t have the money to burn on a $1k processor then just buy the base level chip or mid range and overclock it.
you could get an i7 920 which was stock a 2.66 to get up to 3.4-3.6 on air. For a fraction of the cost. You could even push 3.8 on even more superior cooling.
Now with the new processors like the Sandy Bridge and Ivy and Haswell, yes the K series is a new monster. It basically gives you the ability to overclock in the same ways we are used to with older chips. The non K series chips have some of their dials locked down so people cannot tweak them to their liking, but in reality overclocking is still possible regardless.
I have been overclocking since my first build. An AMD 2400+ I will tell you so long as you have a decent air cooler on it you can make it scream like the best of them.
It just makes more sense to me to buy the lesser of two chips and push it to the limits or above the limits of the more expensive chips.
It has never failed me and I have been doing this awhile. Also read up heavily on any forum you can in regards to your specific chip and mobo if you get lost.
Another thing to remember is stress testing is key to ensuring longevity. You want to make sure you have a stable overclock.
I think that overclocking today is loads easier than it was in the past. (Looking at the days when we would draw with a pencil on our CPUs to unlock L2)
Hope this helps,
-Wooley