Best 7970 for an overclocker?

[dwilson041781]

I've been out of the loop as far as the 7970's and I have read very little such as some being voltage locked etc.

So I'm wondering which 7970 I should choose when considering overclocking. I'm eyeing the 7970 by sapphire and the 7970 ghz vapor x by sapphire. Im also open to other brands.

 

[Fooshnik]

Teh thread.