Well, every review I read seems to indicates that 7970 GHz Edition is pretty much the same as 7970 except it's faster. However, you can also overclock the 7970 to be as fast as 7970 GHz Edition. If that's the case, then what's the point of buying 7970 GHz Edition for $70 more? How can you justify the $70 difference? Does GHz Edition comes with extra features that I don't know?
"As far as performance and functionality goes, the Radeon HD 7970 GHz Edition (7970GE) is a rather straightforward upgrade to the existing Radeon HD 7970. In fact the hardware is absolutely identical right down to the GPU – there have been no changes to the PCB, the cooling, or the VRMs, and even the Tahiti GPU is the same revision that has been shipping in the 7970 since the beginning. Everything the 7970GE adds to the 7970 is accomplished through chip binning and new Catalyst and BIOS features specific to the 7970GE. So in many ways this is the 7970 we’ve already become familiar with, but with more pep in its step."
I would go with the regular 7970 and just overclock it.
If you're not into OC'ing then you'll pay for the factory OC, meaning the "Ghz Edi". If you'll be OC'ing the video card yourself then the stock 7970 is the way to go. As mentioned by PCgamer81, both models have the EXACT same components, meaning a 7970 will reach the same speeds when OC'ed as the 7970 Ghz Edi. The difference being the cooler.
The Ghz Edi's usually have much better coolers (think Sapphire Vapor-X or Gigabyte Windforce) but a non reference Dual or Tri fan setup on a stock 7970 is more than sufficient for keeping an OC'ed card within temp. limits.
A question. Are there reference 7970s with custom coolers in the market? And do they cost much over the reference AMD?
Reference just refers to the design of the cooler in regards to the mounting and size of the board itself. If you're going to purchase an aftermarket cooler or waterblock (good review from Tom's) you want a Reference design card.
This PowerColor 7970 is a reference design.
This Sapphire 7970 is not a reference design.
This MSI 7970 is a reference design but is actually OC'ed to 1010mhz, 10mhz faster than the "Ghz Edi".