Hello, long-time lurker, finally made an account to post =D
It's about that time for me to start looking into a new graphics card. After a good deal of browsing around and comparing, I've set my sights on the HD7970 as the card I want. However, I noticed the GHz edition that AMD released not long after. I know that hardware-wise, the GHz edition is physically identical to the base version. All the upgrades to the chip have been done through "chip binning" (I don't even have the slightest clue what that is) and apparently some BIOS features. I've also heard about PowerTune Tech, but I thought that was a driver-related feature that could be applied to a wide range of AMD cards through CCC (I have my 6950 at +20% PowerTune) so I'm just going to assume that's not a GHz specific feature.
Obviously the main selling point is the clock speeds, but if the hardware is identical, shouldnt both the GHz and base editions have the same overclocking headroom? I know I can OC a base 7970 to the 7970GE's clocks, but I plan on going above that. Does the GHz edition truly have higher OC potential? Or is it just an AMD gimmick? I don't wanna shell out the extra bucks unless I'm getting something of real value over the base 7970. Does anyone have an opinion on whether it's worth the extra dough?
Chip binning is basically testing the chips with the best tolerance before putting them into cards. AMD has a good history of doing this, putting only the best chips on the highest end models. so logically, yes, the ghz edition is likely to get a better overclock, even if just by a slight amount. while comparing price/performance though the stock 7970 will do more bang for your buck and get very close performance overclocked (im talking 1-2% at most). id personally go with the non ghz edition as that small difference will not be noticeable, at all.
you can easily reach the speed of up to 1050Mhz on core 1525Mhz on memory without any voltage tweak on the reference model and it is guaranteed to be 100% stable at anything you throw at it. Some people can reach upto 1125Mhz without overvolting but I don't know if it is 100% stable. Going beyond that requires additional voltage. In fact the Oced reference model is little better than the Ghz editions in terms of performance. In my opinion the only thing you get from a Ghz edition is the warranty.
So, the reference cards are basically the same. AMD built an awesome card but released with clocks a little too low. I DON'T think is a gimmick. You have to keep in mind it is a 15% performance improvement. That is big deal, as a product.
BUT for OVERCLOCKERS there isn't much difference with REFERENCE cards. And the boost feature is kinda a pain. I would choose a base 7970.
however, because GHZ edition is the high end now it WILL get better CUSTOM stuff like coolers and and voltage phases, and manufacturer binning on top of AMD binning. but only IF you go for a high end custom 7970.
Personally id take a base 7970 and take my chances. The process will have improved by now, and they were always clocked too low and always great when overclocked. personally i like sapphire (excellent warranty experience on something that was my fault, and an AMD partner)
Thanks a lot for all the info and advice everybody! I've been looking at the Sapphire that unksol referred to - $360 after rebate plus 3 free games (unfortunately already bought FC3 on release but oh well) is a killer deal. I would like the peace of mind of a high-end like the Twin Frozr GHz simply for the better chip binning and cooling, but I'm a gambler and I'm leaning towards taking my chances with the less expensive Sapphire and hoping I get a good overclocker