What should I expect?

[SS-89]

Well I was long overdue an upgrade so I purchased a used i7 920 D0 and 580GTX. After struggling to get a decent x58 board without paying new z68 prices I then decided that I would rather go Sandybridge. So here I am after dropping a not so insignificant amount on a SB setup.

My change:
Q6600 --> i5 2500k
P5ke --> Z68XP-UD4
4GB 800mhz DDR2 --> 8GB 1600mhz DDR3
GTX 470 --> GTX580 DCUII
Tuniq Tower 120 --> Noctua D14

I'm pleased! I bet you couldn't tell

Anyway enough background and to the question at hand. I've read some sandybridge OCing guides and I know 4.3-4.5GHZ is considered pretty standard overclock from even an average chip but realistically lets say I get a decent chip. What is the maximum overclock I should really consider based on my cooler? Also, again if I get a decent processor what ballpark figures for Vcore would you consider to be representative of a very good clocker? I.e. is 1.3v at a stable 4.8GHZ considered good? Apologies for the noob like questions but I've only ever overclocked on older generation intel cpus and it seems to be a completely different ball game with sandybridge.

Boiled down to one succint sentence: How do I know if I have a good chip?

 

[SS-89]

I obviously undertand that but what is the measurement of a good clocker? like I said is there a standard voltage and OC that people agree is representative of a good chip? For example do average 2500k's get to 4.5GHZ @ 1.35v but good clockers get to 4.5GHZ @ 1.25v?

 

[SS-89]

Thanks as I said I know it is luck of the draw but I just wanted a rough estimate of what is considered good so I know how to measure if I have a decent clocker. I now have something to aim for so I think if I can get 4.6 @1.3v I would be pretty happy.